Polycarbonate copolymer, and heat resistant parts comprising the same

ABSTRACT

An object of the present invention is to provide a polycarbonate copolymer having excellent heat resistance and dimensional stability and heat resistant parts comprising the copolymer and suitable for use in various applications. The present invention is a polycarbonate copolymer comprising 5 to 95 mol % of recurring unit (component a) represented by the following general formula (I): 
                         
and 95 to 5 mol % of recurring unit (component b) represented by the following general formula (II):
 
                         
(wherein R a  to R d  are each independently a hydrogen atom, a hydrocarbon group which may contain an aromatic group having 1 to 9 carbon atoms or a halogen atom, and W is a single bond, a hydrocarbon group which may contain an aromatic group having 1 to 20 carbon atoms or an O, SO, SO 2 , CO or COO group), and various heat resistant parts comprising the copolymer.

TECHNICAL FIELD

The present invention relates to a polycarbonate copolymer and heatresistant parts comprising the copolymer. More specifically, the presentinvention relates to a polycarbonate copolymer having recurring unitscomprising 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, and heat resistantparts comprising the copolymer. Further, the present invention alsorelates to a resin composition comprising the copolymer.

BACKGROUND ART

A polycarbonate obtained by reacting 2,2-bis(4-hydroxyphenyl)propane(hereinafter maybe referred to as “bisphenol A”) with a carbonateprecursor is used as engineering plastic in a wide variety of fields.However, molded articles using the polycarbonate comprising bisphenol Ashow unsatisfactory heat resistance, transparency, moldability anddimensional stability depending on applications, so that the moldedarticles may undergo distortion, fusion or the like.

Hence, a variety of proposals have been made so as to improve heatresistance (refer to Patent Publications 1, 2, 3, 4, 5 and 6).

Further, as an optical application, a polycarbonate copolymer having afluorene structure as typified by 9,9-bis(4-hydroxyphenyl)fluorene hasbeen proposed (refer to Patent Publications 7, 8, 9, 10, 11, 12 and 13).

(Publications on Prior Arts)

Patent Publication 1 JP-A 6-25401 Patent Publication 2 JP-A 7-52270Patent Publication 3 JP-A 6-192411 Patent Publication 4 JP-A 11-306823Patent Publication 5 JP-A 11-35815 Patent Publication 6 JP-A 7-268197Patent Publication 7 JP-A 6-25398 Patent Publication 8 JP-A 6-172508Patent Publication 9 JP-A 2000-319375 Patent Publication 10 JP-A2000-319376 Patent Publication 11 JP-A 2000-319377 Patent Publication 12JP-A 2001-55435 Patent Publication 13 JP-A 2001-55436(Problems to be Solved by the Invention)

An object of the present invention is to provide a polycarbonatecopolymer having excellent heat resistance and dimensional stability, aresin composition comprising the copolymer, and a variety of moldedarticles.

DISCLOSURE OF THE INVENTION

The present invention is a polycarbonate copolymer comprising 5 to 95mol % of recurring unit (component a) represented by the followinggeneral formula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).

Further, the present invention is a heat resistant part comprising apolycarbonate copolymer, the polycarbonate copolymer comprising 5 to 95mol % of recurring unit (component a) represented by the followinggeneral formula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).

A first aspect of the present invention is a part for reflow solderingcomprising a polycarbonate copolymer, the polycarbonate copolymercomprising 60 to 95 mol % of recurring unit (component a) represented bythe following general formula (I):

and 40 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II-1).

A second aspect of the present invention is a light path converting partcomprising a polycarbonate copolymer, the polycarbonate copolymercomprising 50 to 95 mol % of recurring unit (component a) represented bythe following general formula (I):

and 50 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).

A third aspect of the present invention is an optical disk thatcomprises a substrate with a thickness of 0.3 to 1.2 mm which hasembossed pits or guide grooves, a reflective layer formed on thesubstrate and a transparent protective layer with a thickness of 3 to200 μm which is formed on the reflective layer and that reproducesrecorded data based on a change in the light intensity of reflectedlight produced by irradiating the disk with a light beam from thetransparent protective layer side,

-   the substrate substantially comprising a polycarbonate copolymer,-   the polycarbonate copolymer comprising 20 to 95 mol % of recurring    unit (component a) represented by the following general formula (I):

-    and 80 to 5 mol % of recurring unit (component b) represented by    the following general formula (II):

-    (wherein R^(a) to R^(d) are each independently a hydrogen atom, a    hydrocarbon group which may contain an aromatic group having 1 to 9    carbon atoms or a halogen atom, and W is a single bond, a    hydrocarbon group which may contain an aromatic group having 1 to 20    carbon atoms or an O, S, SO, SO₂, CO or COO group), the substrate    showing:-   (A) a flexural modulus of 2,800 to 4,000 MPa,-   (B) a water absorption of 0.3 wt % or lower upon reaching    saturation,-   (C) a tan δ measured at 40° C. and 18 Hz in accordance with ISO    6721-4 of at least 0.020, and-   (D) a deflection temperature under load measured under a load of    1.81 MPa in accordance with ISO 75-1, -2 of 110° C. or higher.

A fourth aspect of the present invention is a plastic mirror comprisinga polycarbonate substrate and a metallic reflective film,

-   the polycarbonate substrate comprising a polycarbonate copolymer,-   the polycarbonate copolymer comprising 20 to 70 mol % of recurring    unit (component a) represented by the following general formula (I):

-    and 80 to 30 mol % of recurring unit (component b) represented by    the following general formula (II-1) and/or (II-2):

-    the polycarbonate substrate showing:-   (A) a glass transition temperature of 120 to 230° C.,-   (B) a water absorption of 0.2 wt % or lower after immersed in water    at 23° C. for 24 hours, and-   (C) a flexural modulus of 2,500 to 4,000 MPa.

A fifth aspect of the present invention is a conductive resincomposition comprising a polycarbonate copolymer and a carbon basedfiller, the polycarbonate copolymer comprising 5 to 95 mol % ofrecurring unit (component a) represented by the following generalformula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).

The fifth aspect includes a tray for conveying an electronic part, thetray comprising a polycarbonate copolymer and a carbon based filler, thepolycarbonate copolymer comprising 5 to 95 mol % of recurring unit(component a) represented by the following general formula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial schematic view of a vertical cross section of a diskin one embodiment of an optical disk of the present invention.

FIG. 2 is a partial schematic view of a vertical cross section of a diskin one embodiment of the optical disk of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Polycarbonate Copolymer

(Component a)

The polycarbonate copolymer of the present invention is produced byusing, as an aromatic dihydroxy component,9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter may beabbreviated as “biscresolfluorene”) represented by the following formula(1).

(Component b)

The polycarbonate copolymer of the present invention is produced byusing, as a copolymerizable component, an aromatic dihydroxy componentrepresented by the following formula (2):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).

As such an aromatic dihydroxy component, any component which isgenerally used as a dihydroxy component of a polycarbonate may be used.Illustrative examples of the component include 4,4′-dihydroxybiphenyl,bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane(“bisphenol A”), 2,2-bis(4-hydroxy-3-methylphenyl)propane (“bisphenolC”), 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,2,2-bis(4-hydroxy-3,3′-biphenyl)propane,2,2-bis(4-hydroxy-3-isopropylphenyl)propane,2,2-bis(3-t-butyl-4-hydroxyphenyl)propane,2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane,2,2-bis(3-bromo-4-hydroxyphenyl)propane,2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane,2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane,2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane,2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane,bis(4-hydroxyphenyl)diphenylmethane, 1,1-bis(4-hydroxyphenyl)cyclohexane(“bisphenol Z”), 1,1-bis(4-hydroxyphenyl)cyclopentane,4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenylether, 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenyl sulfoxide,4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxy-3,3′-dimethyldiphenylsulfone, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide,4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfoxide,4,4′-dihydroxy-3,3′-diphenyldiphenyl sulfone,4,4′-dihydroxy-3,3′-diphenyldiphenyl sulfide,4,4′-dihydroxy-3,3′-diphenyldiphenyl sulfoxide,1,3-bis{2-(4-hydroxyphenyl)propyl}benzene (“bisphenol M”) and1,4-bis{2-(4-hydroxyphenyl)propyl}benzene.

Of these, 2,2-bis(4-hydroxyphenyl)propane (“bisphenol A”) represented bythe following formula (2-1), 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene(“bisphenol M”) represented by the following formula (2-2) and2,2-bis(4-hydroxy-3-methylphenyl)propane (“bisphenol C”) represented bythe following formula (2-3) are suitable.

(Other Copolymerizable Components)

Further, the polycarbonate copolymer of the present invention may be abranched polycarbonate copolymer copolymerized with a phenolic compoundhaving three or more functional groups.

Illustrative examples of the phenolic compound having three or morefunctional groups include phloroglucin, phloroglucide,4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2,4,6-dimethyl-2,4,6-tris-(4-hydroxyphenyl)heptane,1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane,2,2-bis(4,4-bis(4-hydroxyphenyl)cyclohexyl)propane,2,6-bis(2-hydroxy-5-methylbenzyl)-4-methyl phenol,2,6-bis(2-hydroxy-5-isopropylbenzyl)-4-isopropyl phenol,bis(2-hydroxy-3-(2-hydroxy-5-methylbenzyl)-5-methylphenyl)methane,tetrakis(4-hydroxyphenyl)methane, tris(4-hydroxyphenyl)phenyl methane,trisphenol, 2,2-bis(2,4-hydroxyphenyl)propane,bis(2,4-dihydroxyphenyl)ketone, and1,4-bis(4,4-dihydroxytriphenylmethyl)benzene. Of these,1,1,1-tris(4-hydroxyphenyl)ethane is preferred. These may be used aloneor in combination of two or more. The phenolic compound having three ormore functional groups is preferably used in an amount of 0.01 to 5 mol%, more preferably 0.1 to 3 mol %, based on all aromatic dihydroxycomponents, and a branched polycarbonate copolymer having excellentrigidity is obtained.

The present invention includes heat resistant parts comprising the abovecopolymer. Illustrative examples of the heat resistant parts includeparts for reflow soldering, light path converting parts, optical disks,plastic mirrors, and trays for conveying electronic parts.

<First Aspect: Parts for Reflow Soldering>

A first aspect of the present invention relates to a part for reflowsoldering with good transparency which does not undergo deformationduring soldering in a reflow furnace.

In the field of electronic parts, along with a recent reduction in thesize and improvement in the performance of electrical appliances and forthe purpose of improving productivity, a surface mount technology (SMT)which achieves a high part mounting density and has good efficiency hasbeen becoming popular as a method of mounting various electronic partson substrates.

The surface mounting technology refers to a technology for securingelectronic parts on a printed circuit board by placing the electronicparts on the wiring board via creamy solder and then passing the circuitboard through a heating furnace (reflow furnace) so as to melt thesolder.

Illustrative examples of methods which are primarily employed as amethod for heating the substrate in the reflow furnace include a hot airconvention heat transfer method comprising passing the board through hotair which is forcibly circulated, a far-infrared method comprisingheating the board by a far-infrared radiation from above the board orfrom both above and below the board, and a method comprising heating theboard by using hot air and a far-infrared radiation in combination. Insoldering, the circuit board and electronic parts introduced into thereflow furnace reaches high temperatures of 220 to 270° C.

Among electronic parts, there are parts which must have transparencysuch as lenses, prisms and transparent covers. Although these parts arecurrently made of glass or a thermosetting resin in consideration of aproblem of heat resistance, there is a problem that it takes time tomold them. Accordingly, thermoplastic resins having heat resistanceagainst reflow and easy moldability are desired. However, those havingbalanced reflow heat resistance and optical properties are not yetknown.

An object of the first aspect of the present invention is to provide apart for reflow soldering with heat resistance against reflow solderingand excellent transparency and moldability.

(Polycarbonate Copolymer)

A polycarbonate copolymer constituting the part for reflow soldering ofthe first aspect of the present invention comprises a recurring unit(component a) represented by a general formula (I) in an amount of 60 to95 mol %, preferably 65 to 90 mol %, more preferably 70 to 85 mol %, anda recurring unit (component b) represented by a general formula (II-1)in an amount of 40 to 5 mol %, preferably 35 to 10 mol %, morepreferably 30 to 15 mol %.

When the component a is smaller than 60 mol %, its heat resistance as apart for reflow soldering may be poor. Meanwhile, when the component ais larger than 95 mol %, the copolymer shows poor melt flowability andis difficult to mold, and an article molded therefrom shows poortransparency.

(Specific Viscosity)

The polycarbonate copolymer preferably shows a specific viscosity of0.17 to 0.55, more preferably 0.21 to 0.45, which is measured at 20° C.,dissolving 0.7 g of the copolymer in 100 ml of methylene chloride.

(Glass Transition Temperature)

The polycarbonate copolymer preferably shows a glass transitiontemperature (Tg) of 200 to 250° C. which is measured at a temperatureincreasing rate of 20° C./min. The Tg is more preferably 205 to 245° C.When the Tg is lower than 200° C., the reflow heat resistance of anoptical part formed by use of the copolymer is not satisfactory, whilewhen it is higher than 250° C., the copolymer has high melt viscosityand may be difficult to handle in some cases.

(Melt Volume Rate)

The polycarbonate copolymer preferably shows a melt volume rate (MVR)measured at 320° C. under a load of 1.2 kg in accordance with JIS K-7210of at least 0.2 cm³/10 min, more preferably 0.5 cm³/10 min.

Specific examples of the parts for reflow soldering of the presentinvention include lenses and covers for various indicator lamps; cameralenses and lens barrels for camera-incorporated mobile telephones;lenses and covers for light emitting elements such as diodes; covers andsealants for various devices such as transistors and rectifiers; coversand sealants for sensors, ICs (integrated circuits) and the like; andspectral separation/integration devices such as optical guides andoptical fiber cables, e.g., prisms. The parts for reflow soldering ofthe present invention are particularly suitable for lenses, lens barrelsand prisms.

The parts for reflow soldering are molded by any method such as aninjection molding method, a compression molding method, an injectioncompression molding method, an extrusion method and a solution castingmethod.

Optical parts require transparency for different wavelengths accordingto applications. For example, covers and sealants require transparencyfor visible light (400 to 700 nm). Lenses and covers for light emittingelements such as diodes require transparency for the wavelengths oflight emitted from the elements. Further, for optical fibercommunication, wavelengths of 1,300 to 1,600 nm are used, and spectralseparation devices such as prisms for spectral separation of an opticalfiber cable require transparency for the wavelengths.

The polycarbonate copolymer used in the present invention shows goodtransparency at any of these wavelengths. A test piece with a thicknessof 1.0 mm which is formed from the polycarbonate copolymer preferablyhas a transmittance of 60% or higher, more preferably 70% or higher, ateach of the following wavelengths, i.e., 400 nm, 500 nm, 600 nm, 700 nm,1,300 nm, 1,400 nm, 1,500 nm and 1,600 nm.

The part for reflow soldering of the present invention is not deformedeven after treated in a reflow furnace preset such that a peaktemperature of 250° C. lasts for 5 seconds.

<Second Aspect: Light Path Converting Part>

A second aspect of the present invention relates to a light pathconverting part having good heat resistance and thermal stability, avery little birefringence and excellent transparency.

Heretofore, a number of polymethyl methacrylate resins have been used asoptical materials such as lenses, light guide plates and the like sincethey have good transparency and low birefringence. However, while demandfor an improvement in the heat resistance of resins has been increasingin recent years from the viewpoints of an increase in the density ofelectronic equipment and safety, it is hard to say that the polymethylmethacrylate resin has sufficient heat resistance.

Meanwhile, polycarbonate resins are used in various applicationsincluding optical materials due to high transparency and dimensionalstability. However, in view of properties required in optical membersrequiring optical accuracy such as lenses, prisms, light guide platesand light guides, since the polycarbonate resins belong to a group ofcommon plastics which show very distinct birefringence caused byorientation of a molecular chain and show a significant distortioncaused by molding, it is currently difficult to develop use of theresins to optical elements.

As a method of improving the birefringence of the polycarbonate resin, amethod of graft copolymerizing the polycarbonate resin with a styrenebased resin is proposed (JP-A 61-19630 and 63-15822). However, the graftcopolymer comprising the polycarbonate resin and the styrene based resinhas low mechanical strength, is very brittle and is difficult to molddue to poor thermal stability, and in order to improve the mechanicalstrength, its molecular weight must be made high. However, along with anincrease in the molecular weight, its moldability and surface precisiondeteriorate, so that a practical lens cannot be obtained.

As an improved method free of the above problem of the above method, amethod of mixing a polycarbonate resin comprising an aromatic dihydroxycomponent such as bis(4-hydroxy-3,5-dimethylphenyl)propane with anacrylonitrile-styrene copolymer is proposed (JP-A 5-027101). However,although this resin composition has improved transparency andbirefringence, it has a problem that it has low thermal stability and isvery difficult to mold.

Further, a lens with improved heat resistance and a high refractiveindex which comprises a polycarbonate copolymer containing an aromaticdihydroxy component having a fluorene skeleton introduced therein isreported (JP-A 6-018701). However, this publication describesimprovements of heat resistance and a refractive index but does notmention a specific improvement in birefringence.

An object of the second aspect of the present invention is to provide anoptical molded article having a very little birefringence and excellenttransparency.

The present inventor has found that a polycarbonate copolymer obtainedby using a specific dihydric phenol in a specific amount has a verylittle birefringence and that an article molded from the polycarbonatecopolymer has suitable optical properties.

(Polycarbonate Copolymer)

A polycarbonate copolymer constituting the light path converting part ofthe second aspect of the present invention comprises a recurring unit(component a) represented by a general formula (I) in an amount of 50 to95 mol %, preferably 65 to 75 mol %, and a recurring unit (component b)represented by a general formula (II) in an amount of 50 to 5 mol %,preferably 35 to 25 mol %.

Particularly, a polycarbonate copolymer comprising a recurring unit(component a) represented by a general formula (I) in an amount of 50 to95 mol % and a recurring unit (component b) represented by a generalformula (II-1) and/or (II-2) in an amount of 50 to 5 mol % is preferred.

(Re₅₅₀)

The polycarbonate copolymer preferably shows a transmittance at 550 nmof 80% or higher as a molded plate and preferably satisfies thefollowing expression:Re ₅₅₀ /d≦10when retardation at 550 nm is Re₅₅₀ (nm) and the thickness of a portionwhere the transmittance and the retardation are measured is d (mm).

An optical element comprising a general bisphenol A type polycarbonateresin generally shows high retardation, and its value can be reduced bymolding conditions in some cases. However, the range of the conditionsis generally very small, so that molding becomes very difficult to carryout and the general polycarbonate resin often fails to satisfy theexpression. Meanwhile, the polycarbonate copolymer used in the presentinvention shows low retardation caused by orientation of the resin and asmall distortion caused by molding, so that a good optical element canbe obtained therefrom without strict setting of molding conditions.

(Transmittance)

The molded plate preferably has a transmittance (T₅₅₀) at 550 nm of 80%or higher, more preferably 85% or higher. The transmittance is measuredby use of the U-4001 type spectrophotometer of Hitachi, Ltd.

(Specific Viscosity)

The polycarbonate copolymer preferably shows a specific viscosity of0.17 to 0.55, more preferably 0.21 to 0.45, which is measured at 20° C.after 0.7 g of the polymer is dissolved in 100 ml of methylene chloride.

(Glass Transition Temperature)

The polycarbonate copolymer preferably shows a glass transitiontemperature (Tg) of 150 to 250° C. which is measured at a temperatureincreasing rate of 20° C./min. The Tg is more preferably 160 to 245° C.

(5% Weight Reduction Temperature)

The polycarbonate copolymer preferably shows a 5% weight reductiontemperature (Td) of 450° C. or higher, more preferably 480° C. orhigher, as an indication of thermal stability, which is measured at atemperature increasing rate of 20° C./min. When the 5% weight reductiontemperature is lower than 450° C., thermal decomposition during moldingis intense, and it therefore becomes difficult to obtain a good moldedarticle disadvantageously.

(Photoelastic Coefficient)

The polycarbonate copolymer preferably has a photoelastic coefficient of50×10¹³ cm²/dyne or lower, more preferably 45×10¹³ cm²/dyne or lower.When the photoelastic coefficient is higher than 50×10¹³ cm²/dyne, adistortion caused by molding is large, and it may be therefore difficultto use the resulting molded article as a light path converting part insome cases.

(Melt Volume Rate)

The polycarbonate copolymer preferably shows a melt volume rate (MVR)measured at 340° C. under a load of 1.2 kg in accordance with JIS K-7210of at least 1.0 cm³/10 min, more preferably at least 1.5 cm³/10 min.

The light path converting part refers to a lens, prism, light guideplates and light guide which are optical elements used as parts foroptical equipment. More specifically, the lens refers to any lenseswhich have two spherical or non-spherical refractive surfaces and allowlight to pass therethrough. Illustrative examples of the lens include aspherical lens, a non-spherical lens, a Fresnel lens and a microarraylens.

Meanwhile, the prism refers to any molded article having at least twopolished surfaces which are at least not parallel to each other and areformed at a certain angle. Illustrative examples of the prism include arectangular prism, a Porro prism, a direct vision prism, a pentagonalprism, a Daubresse prism, a Henzolt prism, a Spreng prism, a Mohlerprism, a Wollaston prism, an inclined prism and an Abbe prism.

The light path converting part is molded by any method such as aninjection molding method, a compression molding method, an injectioncompression molding method, an extrusion method and a solution castingmethod. From the viewpoints of ease of molding and costs, the light pathconverting part is particularly preferably molded by the injectionmolding method or the injection compression molding method.

The light path converting part preferably shows a transmittance at 550nm of 80% or higher, more preferably 85% or higher, as a molded plate.

Since the light path converting part of the present invention has goodoptical properties as described above, it can be suitably used as anoptical member for electrical and electronic equipment such as a camera,a digital camera, a liquid crystal display, a liquid crystal projector,a copying machine and an optical disk related equipment and as a lightpath converting part such as a splitter or an integrator in opticalcommunication devices.

The light path converting part is preferably a pickup lens, a cameralens, a microarray lens, a projector lens or a prism.

The light path converting part of the present invention has good heatresistance and thermal stability, a very little birefringence andexcellent transparency.

<Third Aspect: Optical Disk>

A third aspect of the present invention relates to an optical diskhaving excellent rigidity and water absorption resistance.

In general optical disks (hereinafter abbreviated as “CD disks”) such asCD and CD-ROM, embossed pits corresponding to recorded data are formedon one surface of a 1.2-mm-thick transparent substrate, and a reflectivefilm made of Al or the like is further formed on the surface. Datarecorded on such a CD disk are reproduced by irradiating the othersurface of the transparent substrate on which the reflective film is notformed with a focused beam.

In contrast, in DVD and DVD-ROM disks (hereinafter abbreviated as “DVDdisks”) having higher recording densities, finer embossed pits thanthose for the CD disk are formed on one surface of a 0.6-mm-thicktransparent substrate, and a reflective film made of Al or the like isfurther formed on the surface. As in the case of the CD disk, datarecorded on the recording surface of such a DVD disk are reproduced byirradiating the other surface of the transparent substrate on which thereflective film is not formed with a focused beam.

As a material of the 0.6-mm-thick substrate, PC (polycarbonate) which isa transparent resin material is generally used. A 0.6-mm-thick PCsubstrate has insufficient mechanical properties and warps as it is.Hence, two 0.6-mm-thick PC substrates are laminated together such thattheir recording surfaces contact with each other. Thereby, mechanicalproperties are secured as a disk having a total thickness of 1.2 mm.

The reason why the thickness of the substrate of the DVD disk is 0.6 mmis to secure a tilt margin. As a track pitch and a pit density increase,a margin for the tilt of the disk decreases. The tilt margin can besecured by reducing the thickness of the substrate from 1.2 mm to 0.6mm. However, since the elastic modulus of a substrate is proportional tothe cube of the thickness thereof from the viewpoint of strength ofmaterials, deterioration in tilt properties which occurs in a substrateproduction process cannot be avoided.

Meanwhile, in the optical disks, in order to increase a transmissionrate in writing and reading data along with the above increase indensity, it is no longer avoidable to spin the disk substrate at higherspeed.

However, in the case of the above constitution of the optical disks, itis difficult to avoid the occurrence of skew due to the followingreasons (1) to (4):

-   (1) Upon injection: Stress is caused by shearing stress when a resin    flows inside a cavity (molecular orientation distortion).-   (2) Completion of filling: When the resin is filled in the cavity,    the flow of the resin immediately stops as the motion of a screw    stops quickly, whereby all inertial forces of the resin and the    screw are applied to the substrate.-   (3) Pressure Keeping: Since pressure is applied to the resin so as    to prevent the back-flow of the resin and prevent the occurrence of    sink caused by contraction in volume until the resin at the time of    injection is gate sealed, pressure distribution occurs throughout    the substrate.-   (4) Cooling: Stress corresponding to temperature distribution occurs    due to thermal shrinkage.

Accordingly, to improve the above constitution of the optical disks, “anoptical recording medium in which at least a recording layer and atransparent protective layer are sequentially formed on a substrate andon which light enters from the transparent protective layer side so asto record and/or reproduce data signals, the above substrate comprisinga first resin layer that forms a surface on which the above recordinglayer is formed and a second resin layer that is laminated on the abovefirst resin layer and that comprises a resin material having a higherflexural modulus than a resin material forming the above first resinlayer” is proposed (JP-A 11-242829).

Meanwhile, even if the problem of the mechanical properties is solved bythe above improvement, optical disks using only one surface side forrecording and reproducing signals undergo deformations due to waterabsorption caused by environmental changes in temperature and humidity.

In the case of the DVD disks, a general polycarbonate substrate showinga water absorption of 0.3 wt % or higher is used. However, since0.6-mm-thick disks are bonded together such that their signal sidescontact with each other, a good water absorption balance is achievedeven if the water absorption is high, so that the resulting DVD disk ishardly deformed. However, in the case of high density disks having ahigh numerical aperture (N.A.), since signals exist on one side of asurface layer, a water absorption balance is varied, so that a problemof deformation by absorption of water occurs. Particularly, an abruptchange is liable to occur during operation of a drive because thetemperature in the device is high and the humidity therein is low duringthe operation of the drive, and such a focus error that signals cannotbe read due to deformation of a disk is liable to occur.

To inhibit such deformation caused by water absorption, “a disk-shapeddata recording medium which comprises a substrate, a recording layerformed on the substrate so as to record data signals and a transparentprotective layer laminated on the recording layer and on which datasignals are recorded and reproduced by light entering from thetransparent protective layer side, the substrate comprising a core layermade of resin and a surface layer made of resin, the surface layer beingintegrated with the core layer, having pits and projections of the datasignals of the recording layer on one surface thereof and having higherflowability than the core layer”, the surface layer of the substrateusing a resin having a water absorption of 0.3 wt % or lower, isproposed (JP-A 2000-11449). The proposal suggests solving the problem bya complicated substrate configuration formed by two color formation orsandwich formation.

Thus, the substrate configuration has become very complicated so as toincrease a recording density, secure a sufficient tilt margin andmechanical strength and prevent a deformation due to water absorptioncaused by environmental changes in temperature and humidity.

A potential cause thereof is unavailability of resins havingsatisfactory properties required as a resin used as a material of asubstrate, i.e., rigidity, damping, heat resistance and waterabsorbability, in development of the optical disk. In particular, in thecase of research and development of polycarbonate based resins which arewidely used as optical disks, a wide variety of polycarbonate basedresins have been developed for the purpose of improving the opticalproperties of the most commonly used polycarbonate resin to which4,4′-dihydroxyphenylpropane is carbonate-bonded (JP-A 2000-327767, forexample).

However, as described above, development of polycarbonate resins havingimproved rigidity, water absorbability, damping and heat resistance isstill unsatisfactory, and it is earnestly desired to provide an opticaldisk having a simpler structure and a high recording density by use of aresin which facilitates design of the recording substrate, includingmoldability as well.

An object of the third aspect of the present invention is to provide anoptical disk having a simple structure and excellent rigidity, damping,heat resistance and water absorbability.

(Structure)

The optical disk of the present invention is an optical disk thatcomprises a substrate with a thickness of 0.3 to 1.2 mm which hasembossed pits or guide grooves, a reflective layer formed on thesubstrate and a transparent protective layer with a thickness of 3 to200 μm which is formed on the reflective layer and that reproducesrecorded data based on a change in the light intensity of reflectedlight produced by irradiating the disk with a light beam from thetransparent protective layer side.

For example, the optical disk of the present invention, as shown in FIG.1, is formed by laminating a light reflecting layer 3, a recording layer4 and a transparent protective layer 5 sequentially on a substrate 2having guide grooves (optical disk 1). On the top surface of thesubstrate 2, phase pits for recording data and tracking servo signalsand guide grooves comprising a given uneven pattern such as fine pitsand projections, e.g., pregrooves, are formed.

Further, an optical disk 2, as shown in FIG. 2, has such a multilayerstructure that a recording film or a reflective layer and a transparentprotective layer are laminated on a substrate 2 having guide groovesmultiple times. For the substrates, light reflecting layer, recordinglayers and transparent protective layers constituting these disks,materials having the same or similar properties can be used.

The optical disk preferably has a recording layer between the reflectivelayer and the transparent protective layer. Further, the embossed pitsor guide grooves are preferably formed on both surfaces of the substrateof the optical disk, reflective layer, recording layer and/ortransparent protective layer are/is also formed on both surface thereof.In addition, the optical disk preferably has a multilayer structure thatthe recording layer or the reflective layer is laminated multiple times.Further, the transparent protective layer of the optical disk of thepresent invention is preferably constituted by the same polycarbonatecopolymer as a polycarbonate copolymer constituting the substrate.

(Polycarbonate Copolymer)

A polycarbonate copolymer used as a material of the optical disk of thepresent invention comprises 20 to 95 mol %, preferably 25 to 70 mol %,more preferably 30 to 60 mol % of recurring unit (component a)represented by a general formula (I).

Another component of the copolymer comprises 80 to 5 mol %, preferably75 to 30 mol %, more preferably 70 to 40 mol % of recurring unit(component b) represented by a general formula (II).

When the proportion of the recurring unit represented by the generalformula (I) is lower than 20 mol %, an optical disk havingunsatisfactory transparency, heat resistance, mechanical physicalproperties, oblique incident birefringence, water absorption, rigidity,transferability or warpage may be obtained.

The polycarbonate copolymer used in the present invention must containthe recurring unit (component a) represented by the general formula (I)in a certain proportion and also contains the recurring unit (componentb) represented by the general formula (II) as another component so as toobtain desired flowability, rigidity and water absorption resistance.

In particular, a polycarbonate copolymer comprising 20 to 95 mol % ofthe recurring unit represented by the general formula (I) and 80 to 5mol % of recurring unit represented by a general formula (II-2) and/orrecurring unit represented by a general formula (II-3) is preferred.

Above all, a polycarbonate copolymer comprising 20 to 70 mol %,preferably 30 to 60 mol %, of the recurring unit represented by thegeneral formula (I) and 80 to 30 mol %, preferably 70 to 40 mol %, ofthe recurring unit represented by the general formula (II-2) ispreferred.

In addition, a polycarbonate copolymer comprising 20 to 70 mol %,preferably 30 to 60 mol %, of the recurring unit represented by thegeneral formula (I) and 80 to 30 mol %, preferably 70 to 40 mol %, ofthe recurring unit represented by the general formula (II-3) ispreferred.

In the optical disk of the present invention, the substrate shows:

-   (A) a flexural modulus of 2,800 to 4,000 MPa,-   (B) a water absorption of 0.3 wt % or lower upon reaching    saturation,-   (C) a tan δ measured at 40° C. and 18 Hz in accordance with ISO    6721-4 of at least 0.020, and-   (D) a deflection temperature under load measured under a load of    1.81 MPa in accordance with ISO 75-1, -2 of 110° C. or higher.    (Flexural Modulus)

The polycarbonate copolymer has a flexural modulus measured inaccordance with ISO178 of 2,800 to 4,000 MPa, more preferably 2,900 to3,900 MPa, much more preferably 3,100 to 3,900 MPa. When the flexuralmodulus is lower than 2,800 MPa, severe surface swing occurs when amolded optical disk spins at high speed, which is undesirable as anoptical disk having a high density storage capacity. Meanwhile, when theflexural modulus is higher than 4,000 MPa, a brittle optical disk isformed, and molding may be difficult to carry out.

(Water Absorption)

The polycarbonate copolymer has a water absorption measured inaccordance with ISO62 upon reaching saturation at 23° C. of 0.3 wt % orlower, preferably 0.28 wt % or lower. When the water absorption ishigher than 0.3 wt %, an optical disk having a metal film formed on thesurface of an optical disk substrate is liable to warp due to absorptionof water and is therefore liable to have tracking errors. A waterabsorption of 0.27 wt % or lower is particularly preferred.

(tan δ)

The polycarbonate copolymer has a tans measured at 40° C. and 18 Hz inaccordance with ISO 6721-4 of at least 0.020, more preferably at least0.025, much more preferably at least 0.027. When the tan δ is smallerthan 0.020, the damping of the resin is small, so that severe surfaceswing occurs when a molded optical disk spins at high speeddisadvantageously.

(Deflection Temperature Under Load)

The polycarbonate copolymer shows a deflection temperature under loadmeasured under a load of 1.81 MPa in accordance with ISO 75-1, -2 of110° C. or higher, preferably 115° C. or higher, more preferably 120° C.or higher. When the deflection temperature under load is low, heatresistance as a disk is unsatisfactory. The deflection temperature underload is generally 150° C. or lower, preferably 140° C. or lower, whenthe polycarbonate copolymer is used in general injection molding.

(Specific Viscosity)

The polycarbonate copolymer preferably shows a specific viscosity of 0.1to 0.5, more preferably 0.15 to 0.4, which is measured at 20° C. after0.7 g of the copolymer is dissolved in 100 ml of methylene chloride.With the specific viscosity within the above range, the polycarbonatecopolymer has good melt flowability and excellent moldability.

(Warpage)

To measure warpage of the optical disk during water absorbing and dryingprocesses, the following measurement method has been used. That is,after the disk is exposed to an environment (environment A) where thetemperature is 30° C. and the humidity is 90% RH until reachingsaturated water absorption, the disk is transferred to an environment(environment B) where the temperature is 23° C. and the humidity is 50%RH, a tilt change at 58 mm from the center which occurs due to thechange of the environment is measured with time, and the maximum valueof the tilt change and a value at which the tilt change is settled arecompared with each other so as to determine a difference (ΔTilt). TheΔTilt of the optical disk at that time is within 1.00 degree, preferablywithin 0.75 degrees, more preferably within 0.60 degrees.

Further, in the case of the optical disk of the present invention, sincedata signals are recorded and reproduced by light entering from thetransparent protective layer 5 side, the substrate 2 does not affectoptical recording and reproduction properties and does not requiretransparency. Although a blend material of at least two resins havingsignificantly different refractive indices has heretofore not beeneasily used as a substrate material for CD, DVD or the like whichrequires conventional optical properties because the blend material hashaze due to light scattering, the substrate 2 of the present inventioncan use even such a blend material, as described above.

To the optical disk substrate of the present invention, otherthermoplastic resins and additives such as a light stabilizer, acoloring agent, an antistatic agent and a lubricant may be added in suchamounts that do not impair transferability and the effect of reducingthe occurrence of warpage in water absorbing and drying processes of amolded disk.

As a mixing method, for example, a vessel equipped with an agitator isprimarily conceivable for a polymer solution, and a method of carryingout mixing by use of a tumbler, a V-shaped blender, a Nauter mixer, aBanbury mixer, a kneading roller, an extruder or the like is used for amolded article such as powder or pellets. In any case, any method can beemployed. However, in consideration of ease of removal of foreign mattermixed in during a mixing process, a method comprising causing theresulting mixture to pass through a filter having appropriate openingsafter mixing in the state of a polymer solution is preferred.

Further, in an extrusion step (pelletization step) of obtaining apellet-shaped resin composition to be injection-molded, the moltenpolymer is preferably passed through a sintered metal filer with afiltration accuracy of 50 μm or lower so as to remove foreign matter. Ifnecessary, such an additive as a phosphorus based antioxidant is alsopreferably added. In any event, a raw material resin before injectionmolding must have the contents of foreign matter, impurities andsolvents reduced to the minimum.

(Production Method of Optical Disk)

Next, a production method of the optical disk will be described.

An optical disk substrate is produced from the above polycarbonatecopolymer by an injection molding method using an injection moldingmachine (including an injection compression molding machine) equippedwith a stamper having surface roughness and pitches and grooves whichsatisfy specifications required for optical disks. In this case, thethickness of the disk substrate is 0.3 to 1.2 mm.

The injection molding machine may be a generally used machine. However,from the viewpoints of inhibiting production of carbides and increasingthe reliability of the disk substrate, a machine whose cylinder andscrew show low adhesion to the resin and which is made of a materialhaving corrosion resistance and abrasion resistance is preferablyemployed. The environment in the molding step is preferably as clean aspossible in consideration of the object of the present invention.Further, it is important to fully dry the material to be molded so as toremove water and be careful not to have retention which may incurdecomposition of the molten resin.

Then, at least a reflective film is formed on one surface of the opticaldisk substrate so as to give an optical disk. As a material thereof,metal elements may be used alone or in combination of two or more. Ofthese, Al alone, Au alone, an Al alloy containing 0.5 to 10 wt %,particularly preferably 3.0 to 10 wt % of Ti or an Al alloy containing0.5 to 10 wt % of Cr is preferably used. Further, the reflective filmcan be formed by such means as ion beam sputtering, DC sputtering or RFsputtering.

In general, in addition to this thin metal film (reflective layer), therecording layer 4 (a phase change film or a dye in the case of DVD-RAMand DVD-R and a magneto optical recording film in the case of a magnetooptical disk) and the transparent protective layer 5 are basicallyformed so as to form the optical disk of the present invention.

As the phase change film, chalcogen or a chalcogen compound is used, forexample. More specifically, Te, Se and chalcogenite based materials suchas Ge—Sb—Te, Ge—Te, In—Sb—Te, In—Se—Te—Ag, In—Se, In—Se—Tl—Co, In—Sb—Se,Bi₂Te₃, BiSe, Sb₂Se₃ and Sb₂Te₃ are used.

Further, as the magneto optical recording film, a perpendicular magneticfilm having magnetooptic properties such as the Kerr effect and theFaraday effect, e.g., a thin amorphous alloy film such as Tb—Fe—Co, isused.

Then, the transparent protective film 5 is formed on the recording layer4. The transparent protective layer 5 is made of a material which allowsa laser beam to pass therethrough. Illustrative examples of the materialinclude thermoplastic resins such as a polycarbonate and an amorphouspolyolefin-based resin and thermosetting resins. In particular, apolycarbonate resin comprising biscresol fluorene in an amount of atleast 20 mol % based on all aromatic dihydroxy components is suitablyused.

Illustrative examples of means for forming the transparent protectivefilm include a method comprising applying a sheet made of athermoplastic resin such as a polycarbonate or an amorphous polyolefinbased resin or a transparent plate such as a glass plate on therecording layer 4, and a method comprising coating an ultraviolet curingresin by a technique such as spin coating and then irradiating thecoated resin with ultraviolet so as to form the transparent protectivefilm. Further, the thickness of the transparent protective film islimited to 3 to 200 μm in order to keep a coma aberration as small aspossible.

Although the basic constitution of the optical disk of the presentinvention has so far been described, dielectric layers may be added tothe constitution so as to control optical properties and thermalproperties. In this case, on the substrate 2, the light reflecting layer3, a first dielectric layer, the recording layer 4, a second dielectriclayer, and the transparent protective layer 5 are formed sequentially.

The optical disk of the present invention is suitable for use as arecording medium having excellent rigidity, damping, heat resistance andwater absorbability and a high density recording capacity.

<Fourth Aspect: Plastic Mirror>

A fourth aspect of the present invention relates to a plastic mirror.More specifically, it relates to a plastic mirror formed from apolycarbonate copolymer which has an excellent flexural modulus,flowability, water absorption resistance and heat resistance and iscapable of very precise printing on the surface of a mold.

Polycarbonate resins are widely used in a variety of fields because theyhave excellent transparency, heat resistance, mechanical properties anddimensional stability. In recent years, they have been actively used forplastic mirrors due to the advantage of transparency thereof.

Meanwhile, to comply with recent reductions in weight, thickness, lengthand size and high speed rotations of a rotating mirror, resins havingimproved melt flowability, mold printability, dimensional stability andrigidity are desired.

Further, a request for higher dimensional stability against absorptionof water for plastic mirrors has been increasingly intense.

An object of the fourth aspect of the present invention is to provide aplastic mirror which satisfies rigidity, water absorption resistance, aflexural modulus and precise printability to a mold and has excellentmelt flowability and heat resistance.

The plastic mirror of the fourth aspect of the present inventioncomprises a polycarbonate substrate and a metallic reflective film, thepolycarbonate substrate comprising a polycarbonate copolymer, thepolycarbonate copolymer comprising 20 to 70 mol %, preferably 30 to 60mol %, of recurring unit (component a) represented by a general formula(I) and 80 to 30 mol %, preferably 70 to 40 mol %, of recurring unit(component b) represented by a general formula (II-1) and/or a generalformula (II-2), the polycarbonate substrate showing:

-   (A) a glass transition temperature of 120 to 230° C.,-   (B) a water absorption of 0.2 wt % or lower after immersed in water    at 23° C. for 24 hours, and-   (C) a flexural modulus of 2,500 to 4,000 MPa.

The plastic mirror is preferably such that the polycarbonate copolymerpreferably comprises 20 to 70 mol %, preferably 30 to 60 mol %, of therecurring unit (component a) represented by the general formula (I) and80 to 30 mol %, preferably 70 to 40 mol %, of the recurring unit(component b) represented by the general formula (II-1) and that thepolycarbonate substrate shows the following properties, i.e.,

-   (A) a glass transition temperature of 160 to 230° C.,-   (B) a water absorption of 0.2 wt % or lower after immersed in water    at 23° C. for 24 hours, and-   (C) a flexural modulus of 2,500 to 3,500 MPa.

The plastic mirror is also preferably such that the polycarbonatecopolymer preferably comprises 20 to 70 mol %, preferably 30 to 60 mol%, of the recurring unit (component a) represented by the generalformula (I) and 80 to 30 mol %, preferably 70 to 40 mol %, of therecurring unit (component b) represented by the general formula (II-2)and that the polycarbonate substrate shows the following properties,i.e.,

-   (A) a glass transition temperature of 120 to 180° C.,-   (B) a water absorption of 0.1 wt % or lower after immersed in water    at 23° C. for 24 hours, and-   (C) a flexural modulus of 2,800 to 4,000 MPa.    (Glass Transition Temperature)

The polycarbonate copolymer has a glass transition temperature of 120 to230° C.

(Water Absorption)

The polycarbonate copolymer has a water absorption measured inaccordance with ISO62 after immersed in water at 23° C. for 24 hours of0.2 wt % or lower, preferably 0.1 wt % or lower. When the waterabsorption is higher than 0.2 wt %, a plastic mirror having a reflectivefilm formed on a substrate for a plastic mirror is apt to warp due toabsorption of water disadvantageously. A water absorption of 0.085 wt %or lower is particularly preferred.

(Flexural Modulus)

The polycarbonate copolymer has a flexural modulus measured inaccordance with ISO178 of 2,500 to 4,000 MPa, more preferably 2,800 to4,000 MPa, much more preferably 2,500 to 3,500 MPa. When the flexuralmodulus is lower than 2,500 MPa, it is difficult to make the thicknessof a molded article small due to insufficient rigidity. Meanwhile, whenthe flexural modulus is higher than 4,000 MPa, a brittle substrate for aplastic mirror is formed, and molding may be difficult to carry out.

(Specific Viscosity)

The polycarbonate copolymer preferably shows a specific viscosity of 0.1to 0.5, more preferably 0.15 to 0.4, which is measured at 20° C. after0.7 g of the copolymer is dissolved in 100 ml of methylene chloride.With the specific viscosity within the above range, the polycarbonatecopolymer has good melt flowability and excellent moldability, and amolded article having optically satisfactory strength is obtainedadvantageously.

(Flowability)

The polycarbonate copolymer preferably shows a flowability in terms ofan MVR value under measurement conditions of 300° C. and 1.2 kgf of 5cm³/10 min or higher, more preferably 20 cm³/10 min or higher, much morepreferably 30 cm³/10 min or higher.

(Other Copolymerizable Components)

In the polycarbonate copolymer, the components a and b desirablyconstitute at least 80 mol %, preferably at least 90 mol %, of allaromatic dihydroxy components. However, the polycarbonate copolymer mayalso contain other dihydroxy components in an amount of not larger than20 mol %, preferably not larger than 10 mol %, of all aromatic dihydroxycomponents.

The other copolymerizable components may be any components other thanthe component a and the component b which are commonly used as dihydroxycomponents of an aromatic polycarbonate. Illustrative examples of suchcopolymerizable components include hydroquinone, resorcinol,4,4′-biphenol, 1,1-bis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane,1,1-bis(4-hydroxyphenyl)-1-phenylethane,1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)pentane,4,4′-(p-phenylenediisopropylindene)diphenol,9,9-bis(4-hydroxyphenyl)fluorene, and1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane.

(Metallic Reflective Film)

As the metallic reflective film, a thin film made of aluminum or thelike is used.

The plastic mirror molding material of the present invention isgenerally obtained by injection molding a polycarbonate resin at a resintemperature of 260 to 340° C. and a mold temperature of 60 to 130° C. orobtained by laminating the injection molded articles together.

(Shape)

The plastic mirror of the present invention is a spherical,non-spherical, hollow, flat or polyhedral mirror which is primarily usedin office automation equipment. Particularly, the plastic mirror of thepresent invention is a polygonal mirror, a projector mirror or a filmmirror but is not limited to these mirrors.

The plastic mirror of the present invention is formed by a polycarbonatecopolymer having low water absorption and a specific flexural modulus ata specific glass transition temperature. Therefore, it has high rigidityand excellent dimensional stability and mold printability at the time ofmolding.

<Fifth Aspect: Conductive Resin Composition, Carrying Tray>

A fifth aspect of the present invention relates to a conductive resincomposition. More specifically, it relates to a conductive resincomposition having good heat resistance, excellent conductivity and lowwater absorption and causing no irritation to skin. Further, the fifthaspect of the present invention relates to a carrying tray made of theresin composition and used for electronic parts such as semiconductors,optical data recording media and hard disks.

A polycarbonate resin is widely used in a variety of fields, alone or asa resin composition which also contains other thermoplastic resins,glass fibers, carbon fibers and the like, in a wide variety of fields asengineering plastic because it has excellent transparency, heatresistance, mechanical properties and dimensional stability. However, inrecent years, materials having excellent heat resistance andconductivity are desired.

As a material having improved heat resistance, a resin compositioncomprising a polycarbonate copolymer having the structure of9,9-bis(4-hydroxyphenyl)fluorene and an inorganic filler is known (JP-A7-268197).

However, the composition has a problem that9,9-bis(4-hydroxyphenyl)fluorene has low reactivity at the time ofpolymerization, so that it is difficult to obtain the polycarbonatecopolymer.

Further, it has been considered a problem that steam derived from9,9-bis(4-hydroxyphenyl)fluorene which is produced by decomposition atthe time of melt extrusion or molding is highly irritating to skin.

Further, the polycarbonate copolymer comprising9,9-bis(4-hydroxyphenyl)fluorene has a problem of having high waterabsorption and poor mechanical properties.

An object of the fifth aspect of the present invention is to provide aconductive resin composition having heat resistance and conductivity,causing no irritation to skin and having low water absorption, and atray for conveying electronic parts which comprises the resincomposition.

The conductive resin composition comprises a polycarbonate copolymer anda carbon based filler. The polycarbonate copolymer comprises 5 to 95 mol%, preferably 7 to 90 mol %, more preferably 10 to 85 mol %, ofrecurring unit (component a) represented by a general formula (I) and 95to 5 mol %, preferably 93 to 10 mol %, more preferably 90 to 15 mol %,of recurring unit (component b) represented by a general formula (II).

When the content of the recurring unit represented by the generalformula. (I) is lower than 5 mol %, it is difficult to improve heatresistance to a sufficient degree. Meanwhile, when the content of therecurring unit represented by the general formula (I) is higher than 95mol %, the melt flowability of the resin composition is low, and moldingis difficult accordingly.

As the polycarbonate copolymer, a copolymer comprising 5 to 95 mol %,preferably 7 to 90 mol %, more preferably 10 to 85 mol %, of therecurring unit represented by the general formula (I) and 95 to 5 mol %,preferably 93 to 10 mol %, more preferably 90 to 15 mol %, of therecurring unit represented by the general formula (II-1) is preferred.

(Specific Viscosity)

The polycarbonate copolymer preferably shows a specific viscosity of0.17 to 0.55, more preferably 0.21 to 0.45, which is measured at 20° C.after 0.7 g of the copolymer is dissolved in 100 ml of methylenechloride.

(Glass Transition Temperature)

The polycarbonate copolymer preferably shows a glass transitiontemperature (Tg) of not lower than 150° C. which is measured at atemperature increasing rate of 20° C./min. The Tg is more preferably155° C.

(Carbon Based Filler)

Meanwhile, illustrative examples of the carbon based filler constitutingthe conductive resin composition of the present invention include carbonfibers, carbon blacks, graphites, carbon nanotubes and fullerenes. Inview of an conductivity improving effect and costs, the carbon fibersand the carbon blacks are particularly preferred.

The carbon fibers are not particularly limited and are various knowncarbon fibers, e.g., carbonaceous fibers and graphitic fibers producedby use of a polyacrylonitrile, cellulose, pitch, rayon, lignin, ahydrocarbon gas or the like, and polyacrylonitrile based carbon fibershaving excellent fiber strength are particularly preferred. Further, thecarbon fibers may have surfaces thereof oxidation-treated by a currentlyknown method as typified by ozone, plasma, nitric acid or electrolysis.The oxidation treatment is preferably carried out so as to increaseadhesion to the resin component. The carbon fibers are generally in theform of a chopped strand, a roving strand, a milled fiber or the like.

To impart conductivity or the like to the carbon fibers, the surfaces ofthe fibers may be metal-coated. The diameter of a metal coated carbonfiber is particularly preferably 6 to 20 μm. The metal coated carbonfiber is a carbon fiber on which a metal such as nickel, copper, cobalt,silver, aluminum, iron or an alloy thereof has been coated by a knownplating method, evaporation method or the like. The metal is preferablyone or more metals selected from nickel, copper and cobalt from theviewpoints of conductivity, corrosion resistance, productivity andeconomical efficiency. The metal coated carbon fiber is particularlypreferably a nickel coated carbon fiber.

Further, as these carbon fibers, those converged by a sizing agent suchas an epoxy resin, an urethane resin or an acrylic resin can be suitablyused. The epoxy resin and/or the urethane resin are/is preferably used.

Illustrative examples of the carbon blacks include conventionally knownketjenblack, acetylene black, furnace black, lamp black, thermal black,channel black, roll black and disk black. Of these carbon blacks,ketjenblack, acetylene black and furnace black are particularlypreferred.

The conductive resin composition of the present invention comprises theabove polycarbonate copolymer and carbon based filler, and the contentsof the components vary depending on situations. However, the content ofthe polycarbonate copolymer is generally 40 to 99 wt %, preferably 50 to90 wt %, and the content of the carbon based filler is generally 60 to 1wt %, preferably 50 to 10 wt %. When the content of the carbon basedfiller is lower than 1 wt %, the effect of improving conductivity isliable to become small, while when the content of the carbon basedfiller is higher than 60 wt %, flowability deteriorates, wherebykneading and molding of the resin may become difficult to carry ourdisadvantageously.

(Inorganic Filler)

In the present invention, various inorganic fillers may be added inaddition to the above carbon based filler so as to improve the rigidityor conductivity of the resin. As these inorganic fillers, glassmaterials, metal based fillers and various mineral fillers can be named.

As the glass materials used as the inorganic fillers, glass fibers,glass milled fibers, glass beads, glass flakes and glass powders can beused, for example.

The glass materials used are not limited to particular glasscompositions such as A glass, C glass and E glass and may contain suchcomponents as TiO₂, Zr₂O, BeO, CeO₂, SO₃ and P₂O₅ in some cases.However, more preferably, E glass (alkali-free glass) is preferredbecause it does not adversely affect the polycarbonate copolymer.

The glass fibers are formed by quenching molten glass while stretchingthe glass into a given fiber form by various methods. Quenching andstretching conditions in the case are also not particularly limited. Asfor the shape of a cross section, glass fibers having variousirregularly shaped cross sections typified by perfectly circular fiberspiled together parallel to one another may be used in addition to commonperfectly circular glass fibers. Further, a mixture of glass fibershaving a perfectly circular cross section and irregularly shaped crosssections may also be used.

The glass fibers have an average fiber diameter of 1 to 25 μm,preferably 5 to 17 μm. When glass fibers having an average fiberdiameter of smaller than 1 μm are used, moldability deteriorates, whilewhen glass fibers having an average fiber diameter of larger than 25 μmare used, the appearance is damaged, and a reinforcing effect is notsufficient.

To impart conductivity or the like to the glass fibers, the surfaces ofthe fibers may be metal-coated. The diameter of the metal coated glassfiber is particularly preferably 6 to 20 μm. The metal coated glassfiber is a glass fiber on which a metal such as nickel, copper, cobalt,silver, aluminum, iron or an alloy thereof has been coated by a knownplating method, evaporation method or the like. The metal is preferablyone or more metals selected from nickel, copper and cobalt from theviewpoints of conductivity, corrosion resistance, productivity andeconomical efficiency.

The metal based fillers used in the present invention do not need to beparticularly limited and refer to metal fibers, metal coated fibers andmetal flakes. Illustrative examples of materials thereof include metalssuch as stainless steel, aluminum, copper and brass. These can be usedin combination of two or more. The diameter of the metal fiber ispreferably 4 to 80 μm, particularly preferably 6 to 60 μm.

As the glass flakes and metal flakes used in the present invention,those having an average particle diameter of 10 to 1,000 microns arepreferred. Further, when the average particle diameter is (a) and thethickness is (c), those having an (a)/(c) ratio of 5 to 500 arepreferred, those having an (a)/(c) ratio of 6 to 450 are more preferred,and those having an (a)/(c) ratio of 7 to 400 are much more preferred.When the average particle diameter is smaller than 10 microns or the (a)(c) ratio is smaller than 5, rigidity is unsatisfactory. Meanwhile, whenthe average particle diameter is larger than 1,000 microns or the(a)/(c) ratio is larger than 500, a molded article having a poorappearance and low Weld strength is obtained disadvantageously. Theaverage particle diameter of the glass flakes and metal flakes iscalculated as a median diameter of weight distribution of particle sizesdetermined by a standard sieve method.

In addition, as the various mineral fillers, whiskers such as potassiumtitanate whiskers, aluminum borate whiskers, silicon carbide whiskersand silicon nitride whiskers, calcium carbonate, magnesium carbonate,dolomite, silica, diatomaceous earth, alumina, iron oxide, zinc oxide,magnesium oxide, calcium sulfate, magnesium sulfate, calcium sulfite,talc, clay, mica, kaolin, asbestos, calcium silicate, montmorillonite,bentonite, wollastonite, graphite, iron powder, lead powder and aluminumpowder can be used, for example.

The inorganic fillers are preferably surface-treated by a silanecoupling agent, a titanate coupling agent, an aluminum coupling agent orthe like. The silane coupling agent is particularly preferred. By thissurface treatment, decomposition of the polycarbonate copolymer isinhibited and adhesion is further improved, so that mechanicalproperties which are an object of the present invention can be improved.

The silane coupling agent is a silane compound represented by thefollowing formula:

(wherein Y is a group having reactivity or an affinity with a resinmatrix, such as an amino group, an epoxy group, a carboxylic acid group,a vinyl group, a mercapto group or a halogen atom, Z¹, Z², Z³ and Z⁴each represent a single bond or an alkylene group having 1 to 7 carbonatoms, the alkylene molecular chain may contain an amide linkage, anester linkage, an ether linkage or an imino linkage, and X¹, X² and X³each represent an alkoxy group, preferably an alkoxy group having 1 to 4carbon atoms or a halogen atom.)

Specific examples of the silane compound include vinyltrichlorsilane,vinyltriethoxysilane, vinyltrimethoxysilane,γ-methacryloxypropyltrimethoxysilane,β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane,N-β(aminoethyl)γ-aminopropyltrimethoxysilane,γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane,γ-mercaptopropyltrimethoxysilane and γ-chloropropyltrimethoxysilane.

Further, these metal based fillers may be converged by an olefin resin,a styrene resin, a polyester resin, an epoxy resin, an urethane resin orthe like. These fibrous fillers may be used alone or in combination oftwo or more.

(Flame Retardant)

The conductive resin composition of the present invention may contain aflame retardant in such an amount that does not impair the object of thepresent invention.

Illustrative examples of the flame retardant include a polycarbonatetype flame retardant of halogenated bisphenol A, an organic salt basedflame retardant, an aromatic phosphoric ester based flame retardant, ahalogenated aromatic phosphoric ester type flame retardant, a fluorinebased flame retardant and a siloxane based flame retardant. Thecomposition may contain one or more of these flame retardants.

Specific examples of the polycarbonate type flame retardant ofhalogenated bisphenol A include a polycarbonate type flame retardant oftetrachlorobisphenol A, a copolymerized polycarbonate type flameretardant of tetrachlorobisphenol A and bisphenol A, a polycarbonatetype flame retardant of tetrabromobisphenol A, and a copolymerizedpolycarbonate type flame retardant of tetrabromobisphenol A andbisphenol A.

Specific examples of the organic salt based flame retardant includedipotassium diphenylsulfone-3,3′-disulfonate, potassiumdiphenylsulfone-3-sulfonate, sodium 2,4,5-trichlorobenzenesulfonate,potassium 2,4,5-trichlorobenzenesulfonate, potassiumbis(2,6-dibromo-4-cumylphenyl)phosphate, sodiumbis(4-cumylphenyl)phosphate, potassium bis(p-toluenesulfone)imide,potassium bis(diphenylphosphoric acid)imide, potassiumbis(2,4,6-tribromophenyl)phosphate, potassiumbis(2,4-dibromophenyl)phosphate, potassium bis(4-bromophenyl)phosphate,potassium diphenylphosphate, sodium diphenylphosphate, potassiumperfluorobutanesulfonate, sodium lauryl sulfate, potassium laurylsulfate, sodium hexadecyl sulfate, and potassium hexadecyl sulfate.

Specific examples of the halogenated aromatic phosphoric ester typeflame retardant include tris(2,4,6-tribromophenyl)phosphate, tris(2,4-dibromophenyl)phosphate and tris(4-bromophenyl)phosphate.

Specific examples of the aromatic phosphoric ester based flame retardantinclude triphenyl phosphate, tris(2,6-xylyl)phosphate,tetrakis(2,6-xylyl)resorcin diphosphate, tetrakis(2,6-xylyl)hydroquinonediphosphate, tetrakis(2,6-xylyl)-4,4′-biphenol diphosphate, tetraphenylresorcin diphosphate, tetraphenyl hydroquinone diphosphate,tetraphenyl-4,4′-biphenol diphosphate, an aromatic polyphosphate whosearomatic ring sources are resorcin and phenol and which contains nophenolic OH group, an aromatic polyphosphate whose aromatic ring sourcesare resorcin and phenol and which contains a phenolic OH group, anaromatic polyphosphate whose aromatic ring sources are hydroquinone andphenol and which contains no phenolic OH group, an aromaticpolyphosphate whose aromatic ring sources are hydroquinone and phenoland which contains a phenolic OH group (hereinafter, “aromaticpolyphosphate” refers to both an aromatic polyphosphate containing aphenolic OH group and an aromatic polyphosphate containing no phenolicOH group), an aromatic polyphosphate whose aromatic ring sources arebisphenol A and phenol, an aromatic polyphosphate whose aromatic ringsources are tetrabromobisphenol A and phenol, an aromatic polyphosphatewhose aromatic ring sources are resorcin and 2,6-xylenol, an aromaticpolyphosphate whose aromatic ring sources are hydroquinone and2,6-xylenol, an aromatic polyphosphate whose aromatic ring sources arebisphenol A and 2,6-xylenol, and an aromatic polyphosphate whosearomatic ring sources are tetrabromobisphenol A and 2,6-xylenol.

Of these flame retardants, as the polycarbonate type flame retardant ofhalogenated bisphenol A, the polycarbonate type flame retardant oftetrabromobisphenol A and the copolymerized polycarbonate oftetrabromobisphenol A and bisphenol A are preferred, and thepolycarbonate type flame retardant of tetrabromobisphenol A is morepreferred.

As the organic salt based flame retardant, dipotassiumdiphenylsulfone-3,3′-disulfonate, potassium diphenylsulfone-3-sulfonateand sodium 2,4,5-trichlorobenzenesulfonate are preferred.

As the aromatic phosphoric ester based flame retardant, triphenylphosphate, tricresyl phosphate, cresyl diphenyl phosphate, resorcinolbis(dixylenylphosphate), bis(2,3-dibromopropyl)phosphate andtris(2,3-dibromopropyl)phosphate are preferred. Of these, triphenylphosphate, tricresyl phosphate and resorcinol bis(dixylenylphosphate)that are aromatic phosphoric ester based flame retardants which do notcause destruction of the ozone layer are most preferred. As the fluorinebased flame retardant, fluorinated polyolefins such as a fluorine resin,e.g., PTFE, particularly those which form fibrils are preferred. As thesiloxane based flame retardant, a polysiloxane containing an aromaticring is preferred.

(Other Resins)

The conductive resin composition of the present invention can alsocontain other resins in such an amount that does not impair the objectof the present invention.

Illustrative examples of the other resins include a polyester resin suchas a polyethylene terephthalate, a polybutylene terephthalate or apolyethylene naphthalate, a polyamide resin, a polyimide resin, apolyether imide resin, a polyurethane resin, a polyphenylene etherresin, a polyphenylene sulfide resin, a polysulfone resin, a polyolefinresin such as a polyethylene or a polypropylene, a polystyrene resin, anacrylonitrile/styrene copolymer (AS resin), anacrylonitrile/butadiene/styrene copolymer (ABS resin), apolymethacrylate resin, a phenol resin and an epoxy resin.

Further, illustrative examples of elastomer include isobutylene/isoprenerubber, styrene/butadiene rubber, ethylene/propylene rubber, acrylicelastomer, silicone rubber, polyester based elastomer, polyamide basedelastomer, MBS rubber, and MAS rubber.

(Production of Conductive Resin Composition)

To produce the conductive resin composition of the present invention,any method is used. For example, a mixing method using a tumbler, aV-shaped blender, a super mixer, a NAUTA mixer, a Banbury mixer, akneading roller, an extruder or the like is used as appropriate. Thethus obtained aromatic polycarbonate resin composition can be formedinto a molded article, directly or after pelletized in a melt extruder,by a generally known method such as an injection molding method, anextrusion method or a compression molding method. Further, to improvethe miscibility of the aromatic polycarbonate resin composition andobtain stable mold releasability and physical properties, use of atwin-screw extruder in melt extrusion is preferred. In addition, whenthe inorganic filler is added, any of a method comprising adding thefiller directly from the opening of the hopper of an extruder or fromthe middle portion of the extruder, a method comprising mixing thefiller with the polycarbonate copolymer in advance, a method comprisingmixing the filler with a portion of the polycarbonate copolymer inadvance so as to prepare a master and then adding the master and amethod comprising adding the master from the middle portion of theextruder can be employed.

The conductive resin composition of the present invention preferably hasa surf ace resistivity value measured in accordance with ASTM D257 of1×10¹² or smaller, more preferably 1×10¹⁰ or smaller, most preferably1×10⁸ or smaller. When the surface resistivity value is larger than1×10¹², conductivity becomes inadequate, and when the resin compositionis used for a tray for conveying electronic equipment, the electronicequipment may be shorted disadvantageously.

The conductive resin composition of the present invention can be handledsafely because steam of the polycarbonate copolymer which is produced atthe time of melt extrusion or molding is free from irritating propertiesand is therefore not irritating to skin.

The thus obtained conductive resin composition of the present inventionis useful for housings and chassis of office automation equipment suchas a personal computer, a word processor, a facsimile, a copying machineand a printer, a carrying tray used for conveying a semiconductor, amemory or a hard disk at the time of production of these components, OAinternal parts such as a tray, chassis, a turn table, a pickup chassisand gears for optical disks and magnetooptical disks such as CD, CD-ROM,CD-R, CD-RW, MO, DVD, DVD-ROM and DVD-R, housings and parts forhousehold electrical appliances such as a television, a videotapeplayer, a DVD player, a video game machine, an electrical washingmachine, an electrical drying machine and a vacuum cleaner, electricaltools such as an electrically powered saw and an electrically powereddrill, optical equipment parts such as a telescope tube, a microscopetube, a camera body, a camera housing and a camera tube, and meterpanels for automobiles.

The conductive resin composition of the present invention has such anadvantage that it has good heat resistance, excellent conductivity andlow water absorption and causes no irritation to skin. Therefore, it issuitable for use as a carrying tray for electronic components such as asemiconductor, an optical recording medium and a hard disk.

(Production Method of Polycarbonate Copolymer)

The polycarbonate copolymers used in the present invention (includingthe first to fifth aspects) are produced by general reaction means knownper se for producing a polycarbonate copolymer, e.g., a methodcomprising reacting an aromatic dihydroxy component with a carbonateprecursor such as phosgene or carbonic acid diester. Next, basic meansfor the production method will be briefly described.

As the carbonate precursor, carbonyl halide, carbonate ester orhaloformate is used. Specific examples thereof include phosgene,diphenyl carbonate, and dihaloformate of an aromatic dihydroxycomponent.

When the aromatic dihydroxy component and the carbonate precursor arereacted with each other by an interfacial polymerization or a fusionmethod so as to produce the polycarbonate resin, a catalyst, a terminalblocking agent and an antioxidant such as a dihydric phenol may be usedas required.

A reaction by the interfacial polymerization method is generally areaction between a dihydric phenol and phosgene and is carried out inthe presence of an acid binder and an organic solvent. As the acidbinder, an alkali metal hydroxide such as sodium hydroxide or potassiumhydroxide or an amine compound such as pyridine is used. As the organicsolvent, a halogenated hydrocarbon such as methylene chloride orchlorobenzene is used. Further, to accelerate the reaction, a catalystsuch as a tertiary amine, a quaternary ammonium compound or a quaternaryphosphonium compound, e.g., triethylamine, tetra-n-butyl ammoniumbromide and tetra-n-butyl phosphonium bromide, can also be used. In thatcase, the reaction temperature is generally 0 to 40° C., the reactiontime is about 10 minutes to 5 hours, and the pH during the reaction ispreferably kept at 9 or higher.

A reaction by the fusion method is generally an ester exchange reactionbetween a dihydric phenol and carbonate ester and is carried out by amethod comprising mixing the dihydric phenol with carbonate ester underheating in the presence of an inert gas and distilling out a producedalcohol or phenol. The reaction temperature varies according to theboiling point of the produced alcohol or phenol but generally rangesfrom 120° C. to 350° C. In the late stage of the reaction, the pressurein the system is reduced to about 1.3×10³ to 1.3×10 Pa so as tofacilitate distilling out the produced alcohol or phenol. The reactiontime is generally about 1 to 4 hours.

Illustrative examples of carbonate ester include esters of an aryl grouphaving 6 to 10 carbon atoms, an aralkyl group and an alkyl group having1 to 4 carbon atoms which may be substituted. Specific examples thereofinclude diphenyl carbonate, ditolyl carbonate,bis(chlorophenyl)carbonate, m-cresyl carbonate, dinaphthyl carbonate,bis(diphenyl)carbonate, dimethyl carbonate, diethyl carbonate, anddibutyl carbonate. Of these, diphenyl carbonate is preferred.

(Polymerization Catalyst)

Further, to increase the rate of polymerization in the fusion method, apolymerization catalyst can be used. As the polymerization catalyst,catalysts which are generally used in an esterification reaction and anester exchange reaction, e.g., alkali metal compounds such as sodiumhydroxide, potassium hydroxide, a sodium salt of a dihydric phenol and apotassium salt of a dihydric phenol, alkaline earth metal compounds suchas calcium hydroxide, barium hydroxide and magnesium hydroxide,nitrogen-containing basic compounds such as tetramethylammoniumhydroxide, tetraethylammonium hydroxide, trimethylamine andtriethylamine, alkoxides of alkali metals and alkaline earth metals,organic salts of alkali metals and alkaline earth metals, zinccompounds, boron compounds, aluminum compounds, silicon compounds,germanium compounds, organotin compounds, lead compounds, osmiumcompounds, antimony compounds, manganese compounds, titanium compoundsand zirconium compounds can be used. These catalysts may be used aloneor in combination of two or more. The amount of thepolymerization-catalyst is selected from a range of 1×10⁻⁸ to 1×10⁻³equivalents, preferably 1×10⁻⁷ to 1×10⁻³ equivalents, more preferably1×10⁻⁶ to 5×10⁻⁴ equivalents, per mole of the dihydric phenol which is araw material.

(Terminal Blocking Agent)

In the polymerization reaction of the polycarbonate copolymer, amonofunctional phenol which is generally used as a terminal blockingagent can be used. Particularly, in the case of a reaction usingphosgene as the carbonate precursor, the monofunctional phenol isgenerally used as a terminal blocking agent so as to adjust a molecularweight, and since the resulting polymer has its terminals blocked bygroups based on the monofunctional phenol, the polymer has betterthermal stability than those whose terminals are not blocked by thegroups based on the monofunctional phenol.

The monofunctional phenol may be any monofunctional phenol which is usedas a terminal blocking agent for a polycarbonate polymer and isgenerally exemplified by a monofunctional phenol which is phenol or alower alkyl substituted phenol represented by the following generalformula:

(wherein A represents a hydrogen atom, a linear or branched alkyl grouphaving 1 to 9 carbon atoms or an aryl alkyl group, and r represents aninteger of 1 to 5, preferably 1 to 3.)

Specific examples of the monofunctional phenol include phenol, p-t-butylphenol, p-cumyl phenol and isooctyl phenol.

Further, other monofunctional phenols such as phenols and benzoicchloride having a long chain alkyl group or an aliphatic ester group asa substituent, and long chain alkyl carboxylic chlorides can also beused. When the terminals of the polycarbonate copolymer are blocked byuse of these monofunctional phenols, they not only serve as a terminalblocking agent or a molecular weight adjuster but also improve the meltflowability of the resin thereby facilitating molding and also improvephysical properties as a substrate. In particular, these monofunctionalphenols have an effect of reducing the water absorption of the resin andare preferably used accordingly. These are represented by the followinggeneral formulae (III-1) to (III-8):

(wherein X is —R—O—, —R—CO—O— or —R—O—CO— wherein R represents a singlebond or a divalent aliphatic hydrocarbon group having 1 to 10 carbonatoms, preferably 1 to 5 carbon atoms, T represents a single bond or thesame bonds as the above X, and n represents an integer of 10 to 50.

Q represents a halogen atom or a monovalent aliphatic hydrocarbon grouphaving 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, prepresents an integer of 0 to 4, Y represents a divalent aliphatichydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbonatoms, and W¹ represents a hydrogen atom, —CO—R¹³, —CO—O—R¹⁴ or R¹⁵wherein R¹³, R¹⁴ and R¹⁵ each represent a monovalent aliphatichydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbonatoms, a monovalent alicyclic hydrocarbon group having 4 to 8 carbonatoms, preferably 5 or 6 carbon atoms or a monovalent aromatichydrocarbon group having 6 to 15 carbon atoms, preferably 6 to 12 carbonatoms.

l represents an integer of 4 to 20, preferably 5 to 10, m represents aninteger of 1 to 100, preferably 3 to 60, particularly preferably 4 to50, Z represents a single bond or a divalent aliphatic hydrocarbon grouphaving 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and W²represents a hydrogen atom, a monovalent aliphatic hydrocarbon grouphaving 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, amonovalent alicyclic hydrocarbon group having 4 to 8 carbon atoms,preferably 5 or 6 carbon atoms or a monovalent aromatic hydrocarbongroup having 6 to 15 carbon atoms, preferably 6 to 12 carbon atoms.

Of these, substituted phenols of (III-1) and (III-2) are preferred. Asthe substituted phenol of (III-1), one in which n is 10 to 30,particularly 10 to 26, is preferred. Specific examples thereof includedecyl phenol, dodecyl phenol, tetradecyl phenol, hexadecyl phenol,octadecyl phenol, eicosyl phenol, docosyl phenol and triacontyl phenol.

Meanwhile, as the substituted phenol of the general formula (III-2), acompound in which X is —R—CO—O— and R is a single bond is appropriate,and a compound in which n is 10 to 30, particularly 10 to 26, issuitable. Specific examples thereof include decyl hydroxybenzoate,dodecyl hydroxybenzoate, tetradecyl hydroxybenzoate, hexadecylhydroxybenzoate, eicosyl hydroxybenzoate, docosyl hydroxybenzoate andtriacontyl hydroxybenzoate.

The position of a substituent in the substituted phenols or substitutedbenzoic chlorides represented by the above general formulae (III-1) to(III-7) is preferably the para or ortho position, and a mixture of bothis preferred.

The above monofunctional phenols are desirably introduced to at least 5mol %, preferably at least 10 mol % of all terminals of the obtainedpolycarbonate copolymer. Further, the monofunctional phenols may be usedalone or in admixture of two or more.

Further, when 9,9-bis(4-hydroxy-3-methylphenyl)fluorene constitutes atleast 80 mol % of all dihydric phenol components in the polycarbonatecopolymer of the present invention, the flowability of the resin maydeteriorate. For this reason, the substituted phenols or substitutedbenzoic chlorides represented by the above general formulae (III-1) to(III-7) are preferably used as a terminal blocking agent.

(Heat Stabilizers)

In the present invention, the above polycarbonate copolymer can containat least one phosphorus compound selected from the group consisting ofphosphoric acid, phosphorous acid, phosphonic acid, phosphonous acid andtheir esters in an amount of 0.0001 to 0.05 wt % based on the copolymer.By addition of the phosphorus compound, the thermal stability of thepolycarbonate copolymer improves, and a decrease in molecular weight anddeterioration in color at the time of molding can be prevented.

The phosphorus compound is at least one phosphorus compound selectedfrom the group consisting of phosphoric acid, phosphorous acid,phosphonic acid, phosphonous acid and their esters and is preferably atleast one phosphorus compound selected from the group consisting of thefollowing general formulae (IV-1) to (IV-4):

wherein R¹ to R¹² each independently represent a hydrogen atom, an alkylgroup having 1 to 20 carbon atoms such as methyl, ethyl, propyl,isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl, octyl,nonyl, decyl, dodecyl, hexadecyl or octadecyl, an aryl group having 6 to15 carbon atoms such as phenyl, tolyl or naphthyl, or an aralkyl grouphaving 7 to 18 carbon atoms such as benzyl or phenethyl.

Further, when two alkyl groups exist in one compound, the two alkylgroups may be bonded together to form a ring.

Illustrative examples of the phosphorus compound represented by theabove formula (IV-1) include triphenyl phosphite, trisnonylphenylphosphite, tris(2,4-di-t-butylphenyl)phosphite, tridecyl phosphite,trioctyl phosphite, trioctadecyl phosphite, didecyl monophenylphosphite, dioctyl monophenyl phosphite, diisopropyl monophenylphosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite,monooctyl diphenyl phosphite,bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite,2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite,bis(nonylphenyl)pentaerythritol diphosphite,bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite,bis(2,4-dicumylphenyl)pentaerythritol diphosphite and distearylpentaerythritol diphosphite.

Illustrative examples of the phosphorus compound represented by theabove formula (IV-2) include tributyl phosphate, trimethyl phosphate,triphenyl phosphate, triethyl phosphate, diphenyl monoorthoxenylphosphate, dibutyl phosphate, dioctyl phosphate and diisopropylphosphate.

Illustrative examples of the phosphorus compound represented by theabove formula (IV-3) includetetrakis(2,4-di-t-butylphenyl)-4,4-diphenylene phosphonite.

Illustrative examples of the phosphorus compound represented by theabove formula (IV-4) include dimethyl benzenephosphonate, diethylbenzenephosphonate and dipropyl benzenephosphonate.

Of these, distearyl pentaerythritol diphosphite, triethyl phosphate,dimethyl benzenephosphonate and bis(2,4-dicumylphenyl)pentaerythritoldiphosphite are preferably used.

The amount of the phosphorus compound is 0.0001 to 0.05 wt %, preferably0.0005 to 0.02 wt %, particularly preferably 0.001 to 0.01 wt %, basedon the polycarbonate copolymer. When the amount is smaller than 0.0001wt %, the above effect is difficult to obtain, while when the amount islarger than 0.05 wt %, the phosphorus compound adversely affects thethermal stability of the polycarbonate copolymer, and hydrolysisresistance is also degraded disadvantageously.

(Antioxidant)

To the polycarbonate copolymer of the present invention, a generallyknown antioxidant can be added so as to prevent oxidation of thecopolymer. Illustrative examples of the antioxidant include a phenolbased antioxidant and a lactone based antioxidant. Specific examples ofthe phenol based antioxidant include triethyleneglycol-bis(3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate),1,6-hexanediol-bis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate),pentaerythritol-tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate),octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,N,N-hexamethylene bis(3,5-di-t-butyl-4-hydroxy-hydrocinnamide),3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester,tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, and3,9-bis{1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5) undecane.

Further, specific examples of the lactone based antioxidant include

-   5,7-di-t-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one, and-   5,7-di-t-butyl-3-(2,3-dimethylphenyl)-3H-benzofuran-2-one.    The antioxidant is preferably added in an amount of 0.0001 to 0.05    wt % based on the polycarbonate copolymer.    (Mold Releasing Agent)

Further, to the polycarbonate copolymer of the present invention, ahigher fatty acid ester of a monohydric or polyhydric alcohol can alsobe added as required. By addition of the higher fatty acid ester of amonohydric or polyhydric alcohol, the mold releasability of the abovepolycarbonate copolymer from a mold at the time of molding is improved,and in molding of an optical article, a molding load is low anddeformation of a molded article by improper mold releasing can beprevented. Further, the addition of the higher fatty acid ester also hasan advantage that the melt flowability of the polycarbonate copolymer isimproved.

The higher fatty acid ester is preferably a partial ester or full esterof a monohydric or polyhydric alcohol having 1 to 20 carbon atoms and asaturated fatty acid having 10 to 30 carbon atoms.

Further, specific examples of the partial ester or full ester of themonohydric or polyhydric alcohol and the saturated fatty acid includemonoglyceride stearate, monosorbitate stearate, monoglyceride behenate,pentaerythritol monostearate, pentaerythritol tetrastearate, propyleneglycol monostearate, stearyl stearate, palmityl palmitate, butylstearate, methyl laurate, isopropyl palmitate, and 2-ethylhexylstearate. Of these, monoglyceride stearate and pentaerythritoltetrastearate are preferably used.

The amount of the ester of the alcohol and the higher fatty acid is 0.01to 2 wt %, preferably 0.015 to 0.5 wt %, more preferably 0.02 to 0.2 wt%, based on the polycarbonate copolymer. When the amount is smaller than0.01 wt %, the above effect is not obtained, while when the amount islarger than 2 wt %, the ester causes stains on the surface of a mold.

(Other Additives)

To the polycarbonate copolymer of the present invention, additives suchas a light stabilizer, a coloring agent, an antistatic agent and alubricant can also be added in such an amount that does not impair heatresistance and transparency. The above additives can be mixed into thepolycarbonate copolymer of the present invention by a given method. Forexample, a mixing method using a tumbler, a V-shaped blender, a NAUTAmixer, a Banbury mixer, a kneading roller, an extruder or the like isused as appropriate.

EXAMPLES

Hereinafter, the present invention will be further described withreference to Examples. However, the present invention is not limited tothese Examples. In Examples, “parts” mean “parts by weight”.

Examples 1 to 3 and Comparative Example 1 Part for Reflow Soldering

Physical properties were evaluated by the following methods.

(1) Specific Viscosity

This is measured at a temperature of 20° C. after 0.7 g of polymer isdissolved in 100 ml of methylene chloride.

(2) Glass Transition Point (Tg)

This is measured at a temperature increasing rate of 20° C./min by useof the 2910 type DSC of TA INSTRUMENTS JAPAN CO., LTD.

(3) Melt-Volume Rate (MVR)

This is shown by a polymer amount (cm³) flown out in 10 minutes at 320°C. under a load of 1.2 kg by use of the L251-11 type MFR measuringdevice of TECHNOL SEVEN CO., LTD. in accordance with JIS K-7210.

(4) Transmittance

The transmittance of a test piece prepared by injection molding andhaving a thickness of 1.0 mm, a width of 10 mm and a length of 20 mm atwavelengths of 400 nm, 500 nm, 600 nm, 700 nm, 1,300 nm, 1,400 nm, 1,500nm and 1,600 nm is measured by use of the U-4001 type spectrophotometerof HITACHI, LTD.

(5) Reflow Heat Resistance

a. Test Piece

A test, piece prepared by injection molding and having a thickness of1.0 mm, a width of 10 mm and a length of 20 mm is dried under reducedpressure at 120° C. for 10 hours. This test piece is treated by a reflowfurnace (product of Asahi Engineering Co., Ltd., TPF-20L) using bothinfrared light and hot air. The heating temperature pattern is set suchthat a peak temperature of 250° C. lasts for 5 seconds after heating at150° C. for 60 seconds. When the molded piece after the reflow treatmentis not deformed, it is evaluated as “◯”, and when it is deformed, it isevaluated as “x”.

b. Lens

A flat convex lens prepared by injection molding and having an externaldiameter of 2.0 mm, a thickness at the center of 0.80 mm and a focaldistance of 2.0 mm is dried under reduced pressure at 120° C. for 10hours. This test piece is treated by a reflow furnace (product of AsahiEngineering Co., Ltd., TPF-20L) using both infrared light and hot air.The heating temperature pattern is set such that a peak temperature of250° C. lasts for 5 seconds after heating at 150° C. for 60 seconds.When the amount of change in the focal distance of the flat convex lensafter the reflow treatment is smaller than 0.10 mm, it is evaluated as“◯”, and when the amount of change is 0.10 mm or larger or the lens isdeformed, it is evaluated as “×”.

Example 1

(Polymerization)

To a reactor equipped with a thermometer, agitator and ref luxcondenser, 2,270 parts of ion exchange water and 444 parts of 48% sodiumhydroxide aqueous solution were added, and 76.8 parts of bisphenol A,509.1 parts of 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinaftermay be abbreviated as “biscresolfluorene”) and 1.2 parts of hydrosulfitewere then dissolved. Then, after 1,430 parts of methylene chloride wasadded, 225 parts of phosgene was blown into the mixture at 18 to 23° C.in 60 minutes under agitation. After completion of the blowing ofphosgene, 11.4 parts of p-t-butyl phenol and 6.9 parts of 48% sodiumhydroxide aqueous solution were added, and the resulting mixture wasagitated at 25 to 30° C. for 40 minutes, thereby completing thereaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. Thereby, 600 parts of whitishyellow polymer having a molar ratio of bisphenol A/biscresolfluorene of20:80, a specific viscosity of 0.244 and a Tg of 223° C. was obtained(yield: 95%).

(Molding)

To this polycarbonate resin powder, 0.050% oftris(2,4-di-t-butylphenyl)phosphite, 0.010% ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 0.030% ofpentaerythritol tetrastearate were added, and the mixture was pelletizedby use of a vented φ30-mm twin screw extruder and then injection moldedinto a molded piece having a thickness of 1.0 mm, a width of 10 mm and alength of 20 mm by use of the N-20C injection molding machine of JapanSteel Works, LTD. at a cylinder temperature of 340° C. and a moldtemperature of 150° C. The transmittance of the molded piece wasmeasured, and reflow heat resistance thereof was tested. The results areshown in Table 1.

(Lens)

Further, a flat convex lens having an external diameter of 2.0 mm, athickness at the center of 0.80 mm and a focal distance of 2.0 mm wasinjection molded from the above pellet by use of the N-20C injectionmolding machine of Japan Steel Works, LTD. at a cylinder temperature of340° C. and a mold temperature of 150° C. The transmittance of the lenswas measured, and reflow heat resistance thereof was tested. The resultsare shown in Table 1.

Example 2

(Polymerization)

To a reactor equipped with a thermometer, agitator and ref luxcondenser, 2,060 parts of ion exchange water and 404 parts of 48% sodiumhydroxide aqueous solution were added, and 111.6 parts of bisphenol A,431.7 parts of 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinaftermay be abbreviated as “biscresolfluorene”) and 1.1 parts of hydrosulfitewere then dissolved. Then, after 1,390 parts of methylene chloride wasadded, 210 parts of phosgene was blown into the mixture at 18 to 23° C.in 60 minutes under agitation. After completion of the blowing ofphosgene, 11.0 parts of p-t-butyl phenol and 6.7 parts of 48% sodiumhydroxide aqueous solution were added, and the resulting mixture wasagitated at 25 to 30° C. for 40 minutes, thereby completing thereaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. Thereby, 560 parts of whitishyellow polymer having a molar ratio of bisphenol A/biscresolfluorene of30:70, a specific viscosity of 0.258 and a Tg of 216° C. was obtained(yield: 94%).

(Molding)

To this polycarbonate resin powder, 0.050% oftris(2,4-di-t-butylphenyl)phosphite, 0.010% ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 0.030% ofpentaerythritol tetrastearate were added, and the mixture was pelletizedby use of a vented φ30-mm twin screw extruder and then injection moldedinto a molded piece having a thickness of 1.0 mm, a width of 10 mm and alength of 20 mm by use of the N-20C injection molding machine of JapanSteel Works, LTD. at a cylinder temperature of 330° C. and a moldtemperature of 140° C. The transmittance of the molded piece wasmeasured, and reflow heat resistance thereof was tested. The results areshown in Table 1.

(Lens)

Further, a flat convex lens having an external diameter of 2.0 mm, athickness at the center of 0.80 mm and a focal distance of 2.0 mm wasinjection molded from the above pellet by use of the N-20C injectionmolding machine of Japan Steel Works, LTD. at a cylinder temperature of330° C. and a mold temperature of 140° C. The transmittance of the lenswas measured, and reflow heat resistance thereof was tested. The resultsare shown in Table 1.

Example 3

(Polymerization)

621 parts of whitish yellow polymer having a molar ratio of bisphenolA/biscresolfluorene of 15:85, a specific viscosity of 0.240 and a Tg of232° C. was obtained (yield: 94%) in the same manner as in Example 1except that the amount of bisphenol A used in Example 1 was changed to57.6 parts and that the amount of biscresolfluorene used in Example 1was changed to 540.9 parts.

(Molding)

To this polycarbonate resin powder, 0.050% oftris(2,4-di-t-butylphenyl)phosphite, 0.010% ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 0.030% ofpentaerythritol tetrastearate were added, and the mixture was pelletizedby use of a vented φ30-mm twin screw extruder and then injection moldedinto a molded piece having a thickness of 1.0 mm, a width of 10 mm and alength of 20 mm by use of the N-20C injection molding machine of JapanSteel Works, LTD. at a cylinder temperature of 350° C. and a moldtemperature of 165° C. The transmittance of the molded piece wasmeasured, and reflow heat resistance thereof was tested. The results areshown in Table 1.

(Lens)

Further, a flat convex lens having an external diameter of 2.0 mm, athickness at the center of 0.80 mm and a focal distance of 2.0 mm wasinjection molded from the above pellet by use of the N-20C injectionmolding machine of Japan Steel Works, LTD. at a cylinder temperature of350° C. and a mold temperature of 165° C. The transmittance of the lenswas measured, and reflow heat resistance thereof was tested. The resultsare shown in Table 1.

Comparative Example 1

(Polymerization)

To a reactor equipped with a thermometer, agitator and reflux condenser,2,270 parts of ion exchange water and 444 parts of 48% sodium hydroxideaqueous solution were added, and 7.68 parts of bisphenol A, 623.6 partsof biscresolfluorene and 1.2 parts of hydrosulfite were then dissolved.Then, after 2,000 parts of chloroform was added, 225 parts of phosgenewas blown into the mixture at 18 to 23° C. in 60 minutes underagitation. After completion of the blowing of phosgene, 10.1 parts ofp-t-butyl phenol and 6.9 parts of 48% sodium hydroxide aqueous solutionwere added, and the resulting mixture was agitated at 25 to 30° C. for40 minutes, thereby completing the reaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. Thereby, 637 parts of whitishyellow polymer having a molar ratio of bisphenol A/biscresolfluorene of2:98, a specific viscosity of 0.245 and a Tg of 238° C. was obtained(yield: 93%).

(Molding)

To this polycarbonate resin powder, 0.050% oftris(2,4-di-t-butylphenyl)phosphite, 0.010% ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 0.030% ofpentaerythritol tetrastearate were added, and the mixture was pelletizedby use of a vented φ30-mm twin screw extruder and then injection moldedinto a molded piece having a thickness of 1.0 mm, a width of 10 mm and alength of 20 mm by use of the N-20C injection molding machine of JapanSteel Works, LTD. at a cylinder temperature of 360° C. and a moldtemperature of 170° C. The transmittance of the molded piece wasmeasured, and reflow heat resistance thereof was tested. The results areshown in Table 1.

(Lens)

Further, a flat convex lens having an external diameter of 2.0 mm, athickness at the center of 0.80 mm and a focal distance of 2.0 mm wasinjection molded from the above pellet by use of the N-20C injectionmolding machine of Japan Steel Works, LTD. at a cylinder temperature of360° C. and a mold temperature of 170° C. The transmittance of the lenswas measured, and reflow heat resistance thereof was tested. The resultsare shown in Table 1.

TABLE 1 Unit Ex. 1 Ex. 2 Ex. 3 C. Ex. 1 Composition RatioBiscresolfluorene 80 70 85 98 (mol %) Bisphenol A 20 30 15 2 Results ofMVR cm³/10 min 1.5 2.5 0.6 0.1 Evaluations Transmittance   400 nm % 68.968.5 66.6 58.9   500 nm % 80.2 80.5 80.2 78.0   600 nm % 82.3 82.5 81.881.2   700 nm % 84.0 84.6 84.0 83.3 1,300 nm % 88.5 88.7 87.9 87.6 1,400nm % 81.7 81.5 81.8 81.4 1,500 nm % 86.5 86.7 86.3 85.0 1,600 nm % 84.384.3 84.5 83.9 Reflow Heat Test Piece ◯ ◯ ◯ ◯ Resistance Lens ◯ ◯ ◯ ◯Ex.: Example, C. Ex.: Comparative Example

Examples 4 to 18 and Comparative Examples 2 to 7 Light Path ConvertingPart

Physical properties were evaluated by the following methods.

(1) Specific Viscosity

This is measured at a temperature of 20° C. after 0.7 g of polymer isdissolved in 100 ml of methylene chloride.

(2) Glass Transition Point (Tg)

This is measured at a temperature increasing rate of 20° C./min by useof the 2910 type DSC of TA INSTRUMENTS JAPAN CO., LTD.

(3) 5% Weight Reduction Temperature (Td)

This is measured at a temperature increasing rate of 20° C./min by useof the 2950 type TGA of TA INSTRUMENTS JAPAN CO., LTD.

(4) Photoelastic Coefficient

This is measured by use of the photoelasticity measuring device PA-150of Riken Keiki-Co., Ltd.

(5) Transmittance (T₅₅₀)

The transmittance at 550 nm of a prepared molded plate is measured byuse of the U-4001 type spectrophotometer of Hitachi, Ltd.

(6) Retardation (Re₅₅₀)

The retardation at 550 nm of a prepared molded plate is measured by useof the M-220 type ellipsometer of JASCO Corporation.

(Polymerization)

EX-PC1

To a reactor equipped with a thermometer, agitator and reflux condenser,2,050 parts of ion exchange water and 434 parts of 48% sodium hydroxideaqueous solution were added, and 111.6 parts of bisphenol A (hereinaftermay be abbreviated as “BPA”), 431.7 parts of9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter may beabbreviated as “BCF”) and 1.1 parts of hydrosulfite were dissolved.Then, after 1,360 parts of methylene chloride was added, 215 parts ofphosgene was blown into the mixture at 18 to 23° C. in 60 minutes underagitation. After completion of the blowing of phosgene, 11.0 parts ofp-t-butyl phenol and 67 parts of 48% sodium hydroxide aqueous solutionwere added, and the resulting mixture was agitated at 25 to 30° C. for45 minutes, thereby completing the reaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. Thereby, 550 parts of whitishyellow polymer powder having a molar ratio of BPA/BCF of 30:70, aspecific viscosity of 0.260 and a Tg of 215° C. was obtained (yield:92%).

EC-PC2

To a reactor equipped with a thermometer, agitator and reflux condenser,3,608 parts of ion exchange water and 482 parts of 48% sodium hydroxideaqueous solution were added, and 156.1 parts of1,3-bis{2-(4-hydroxyphenyl)propyl}benzene (hereinafter may beabbreviated as “BPM”), 461.0 parts of BCF and 1.3 parts of hydrosulfitewere then dissolved. Then, after 1,704 parts of methylene chloride wasadded, 215 parts of phosgene was blown into the mixture at 18 to 23° C.in 60 minutes under agitation. After completion of the blowing ofphosgene, 12.5 parts of p-t-butyl phenol and 69 parts of 48% sodiumhydroxide aqueous solution were added, and the resulting mixture wasagitated at 25 to 30° C. for 45 minutes, thereby completing thereaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. Thereby, 619 parts of whitishyellow polymer powder having a molar ratio of BPM/BCF of 27:73, aspecific viscosity of 0.260 and a Tg of 212° C. was obtained (yield:92%).

EX-PC3

560 parts of whitish yellow polymer having a molar ratio of BPA/BCF of33:67, a specific viscosity of 0.262 and a Tg of 212° C. was obtained(yield: 94%) in the same manner as in production of EX-PC1 except thatthe amount of BPA used in the production of EX-PC1 was changed to 124.4parts and that the amount of BCF used in the production of EX-PC1 waschanged to 418.9 parts.

EX-PC4

630 parts of whitish yellow polymer having a molar ratio of BPM/BCF of45:55, a specific viscosity of 0.280 and a Tg of 190° C. was obtained(yield: 95%) in the same manner as in production of EX-PC2 except thatthe amount of BPM used in the production of EX-PC2 was changed to 260.1parts and that the amount of BCF used in the production of EX-PC2 waschanged to 347.3 parts.

EX-PC5

595 parts of whitish yellow polymer having a molar ratio of BPA/BCF of20:80, a specific viscosity of 0.250 and a Tg of 220° C. was obtained(yield: 94%) in the same manner as in the production of EX-PC1 exceptthat the amount of BPA used in the production of EX-PC1 was changed to79.3 parts and that the amount of BCF used in the production of EX-PC1was changed to 504.6 parts.

CEX-PC1

584 parts of whitish yellow BPA homopolymer having a specific viscosityof 0.280 and a Tg of 144° C. was obtained (yield: 95%) in the samemanner as in the production of EX-PC1 except that the amount of BPA usedin the production of EX-PC1 was changed to 605.3 parts, BCF was notadded and the amount of p-t-butyl phenol was changed to 13.0 parts.

CEX-PC2

40 parts of polycarbonate resin comprising, as an aromatic dihydroxycomponent, bis(4-hydroxy-3,5-dimethylphenyl)propane having a specificviscosity of 0.550 and 60 parts of acrylonitrile-styrene copolymerhaving a weight average molecular weight of 100,000 and copolymerizedwith 10% of acrylonitrile component were dry blended by use of atumbler.

Examples 4 to 8 and Comparative Examples 2 and 3

(Molded Piece)

To the prepared resins, 0.050% of bis(2,4-dicumylphenyl)pentaerythritoldiphosphite and 0.10% of pentaerythritol tetrastearate were added, andthe resulting mixtures were pelletized by use of a vented φ30-mm singlescrew extruder and then injection molded into molded plates each havinga thickness of 1.0 mm, a width of 1.0 mm and a length of 2.0 mm undermolding conditions shown in Table 2 by use of the N-20C injectionmolding machine of Japan Steel Works, LTD. The transmittances andretardations of the molded plates were measured. The results are shownin Table 2.

TABLE 2 Composition Evaluation Results Molding Conditions Evaluation PCRatio Photoelastic Cylinder Mold Results Item Resins BCF BPA BPM Tg TdCoefficient Temperature Temperature T₅₅₀ Re₅₅₀ Unit — mol % mol % mol %° C. ° C. ×10¹³ cm²/dyne ° C. ° C. % nm Ex. 4 EX-PC1 70 30 215 495 38350 140 89 1.5 Ex. 5 EX-PC2 73 27 212 482 30 350 140 88 1.2 Ex. 6 EX-PC367 33 212 497 39 350 140 89 1.3 Ex. 7 EX-PC4 55 45 165 490 40 320 125 887.3 Ex. 8 EX-PC5 80 20 220 485 35 350 140 89 5.4 C. Ex. 2 CEX-PC1 100144 497 80 300 115 90 72 C. Ex. 3 CEX-PC2 129 403 18 270 90 88 9.6 Ex.:Example, C. Ex.: Comparative Example

Examples 9 to 13 and Comparative Examples 4 and 5

(Lens)

To the prepared resins, 0.050% of bis(2,4-dicumylphenyl)pentaerythritoldiphosphite and 0.10% of pentaerythritol tetrastearate were added, andthe mixtures were pelletized by use of a vented φ30-mm single screwextruder and then injection molded into flat convex lenses each havingan external diameter of 2.0 mm, a thickness at the center of 0.80 mm anda focal distance of 2.0 mm under molding conditions shown in Table 3 byuse of the N-20C injection molding machine of Japan Steel Works, LTD.

At the front and back of the molded flat convex lens, polarizing plateswhose phase differences were shifted by 90° were disposed. White lightwas irradiated to one of the polarizing plates, and interference colorappearing on the flat convex lens was observed visually so as toevaluate the degree of birefringence based on the following criteria.

-   ⊚: No interference stripes-   ◯: One interference stripe-   ×: Two or more interference stripes    The results of molding and evaluation are shown in Table 3.

TABLE 3 Composition Molding Conditions PC Ratio Cylinder Mold EvaluationResults Item Resins BCF BPA BPM Temperature Temperature MoldabilityBirefringence Unit — mol % mol % mol % ° C. ° C. % ⊚/◯/X Ex. 9 EX-PC1 7030 350 140 No Problem ⊚ Ex. 10 EX-PC2 73 27 350 140 No Problem ⊚ Ex. 11EX-PC3 67 33 350 140 No Problem ⊚ Ex. 12 EX-PC4 55 45 320 125 No Problem◯ Ex. 13 EX-PC5 80 20 350 140 No Problem ◯ C. Ex. 4 CEX-PC1 100 320 115No Problem X C. Ex. 5 CEX-PC2 300 100 Large Amount of X Cracked Gas,Difficult to Mold Ex.: Example, C. Ex.: Comparative Example

Examples 14 to 18 and Comparative Examples 6 and 7

(Prism)

To the prepared resins, 0.030% of bis(2,4-dicumylphenyl)pentaerythritoldiphosphite and 0.15% of pentaerythritol tetrastearate were added, andthe mixtures were pelletized by use of a vented φ30-mm single screwextruder and then injection molded into rectangular prisms each having asize of 20.0 mm×28.3 mm×20.0 mm under molding conditions shown in Table4 by use of the N-20C injection molding machine of Japan Steel Works,LTD.

At the front and back of the molded prism, polarizing plates whose phasedifferences were shifted by 90° were placed. White light was irradiatedto one of the polarizing plates, and interference color appearing on theprism was observed visually so as to evaluate the degree ofbirefringence based on the following criteria.

-   ⊚: No interference stripes-   ◯: One interference stripe-   x: Two or more interference stripes

TABLE 4 Composition Molding Conditions PC Ratio Cylinder Mold EvaluationResults Item Resins BCF BPA BPM Temperature Temperature MoldabilityBirefringence Unit — mol % mol % mol % ° C. ° C. % ⊚/◯/X Ex. 14 EX-PC170 30 360 150 No Problem ⊚ Ex. 15 EX-PC2 73 27 360 150 No Problem ⊚ Ex.16 EX-PC3 67 33 360 150 No Problem ⊚ Ex. 17 EX-PC4 55 45 360 130 NoProblem ◯ Ex. 18 EX-PC5 80 20 365 155 No Problem ◯ C. Ex. 6 CEX-PC1 100350 125 No Problem X C. Ex. 7 CEX-PC2 300 110 Large Amount of X CrackedGas, Difficult to Mold Ex.: Example, C. Ex.: Comparative Example

Examples 19 to 23 and Comparative Examples 8 and 9 Optical Disk

Physical properties were evaluated by the following methods.

(1) Deflection Temperature under Load

This is measured under a load of 1.81 MPa in accordance with ISO75-1,-2.

(2) Saturated Water Absorption

A polymer is immersed in pure water at 23° C., and saturated waterabsorption when an amount of change in a day reaches 0.01% or lower ismeasured in accordance with ISO62.

(3) Flexural Modulus

After a pellet is dried at 120° C. for 5 hours, it is injection moldedinto a test piece at a cylinder temperature of 290° C. by use of aninjection molding machine (SG-150 of Sumitomo Heavy Industries, Ltd.).The flexural modulus of the test piece is measured in accordance withISO178.

(4) Initial Mechanical Properties

A disk substrate having a diameter of 120 mm and a thickness of 1.2 mmwas injection molded from each pellet by use of M35B-D-DM of MEIKI CO.,LTD. Table 5 shows molding conditions for each substrate. Thereafter, onthe disk substrate obtained by injection molding, a reflective film, adielectric layer 1, a phase change recording film and a dielectric layer2 are deposited by sputtering, and a thin polycarbonate film cover layeris laminated thereon so as to obtain an optical disk substrate ofinterest.

Then, spacers are inserted between the disks so as to prevent the disksfrom contacting with each other, and the resulting disks are left tostand at a temperature of 23° C. and a humidity of 50% RH at least fortwo days. Tilt (initial substrate shape) is evaluated by the threedimensional shape measuring equipment DLD-3000U of Japan EM Co., Ltd.when a change in tilt with respect to thermal contraction and anenvironmental change is stabilized, and it is taken as initialmechanical properties.

(5) ΔTilt

After a disk substrate whose initial mechanical properties has beenevaluated is exposed to an environment (environment A) where thetemperature is 30° C. and the humidity is 90% RH until reachingsaturated water absorption, the disk substrate is transferred to anenvironment (environment B) where the temperature is 23° C. and thehumidity is 50% RH. After the transfer, a tilt change at 58 mm from thecenter which occurs due to the change of the environment is measuredwith time by the three dimensional shape measuring equipment DLD-3000Uof Japan EM Co., Ltd. The difference between the maximum value of thetilt change and a value at which the tilt change is settled is taken asΔTilt.

(6) Damping (tan δ)

This is measured at 40° C. and 18 Hz by use of RDAII of REOMETRICS CO.,LTD. in accordance with ISO 6721-4.

Example 19

(Polymerization)

To a reactor equipped with a thermometer, agitator, reflux condenser andphosgene blowing tube, 31,500 parts of ion exchange water and 1,730parts of sodium hydroxide were added, and 2,040 parts of9,9-bis(3-methyl-4-hydroxyphenyl)fluorene (hereinafter may beabbreviated as “BCF”), 2,802 parts of4,4′-(m-phenylenediisopropylidene)diphenol (hereinafter may beabbreviated as “BPM”) and 10 parts of hydrosulfite were dissolved. Then,after 13,770 parts of methylene chloride was added, 1,670 parts ofphosgene was blown into the mixture at 16 to 18° C. in 60 minutes underagitation. After completion of the blowing of phosgene, 81 parts ofp-t-butyl phenol and 178 parts of sodium hydroxide were added, 4 partsof triethylamine was further added, and the resulting mixture wasagitated at 30° C. for 1 hour, thereby completing the reaction. Aftercompletion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. Thereby white powder having amolar ratio of BCF/BPM of 40:60 was obtained. This powder had a specificviscosity of 0.283.

To this powder, 0.003 parts of tris(2,4-di-t-butylpyhenyl)phosphite,0.005 parts of trimethyl phosphate and 0.045 parts of monoglyceridestearate were added based on 100 parts of the powder. Then, the powderwas melt-kneaded by use of a vented twin screw extruder (KTX-46 of KobeSteel, Ltd.) at a cylinder temperature of 260° C. while being deaerated,pelletized, and then injection molded into a disk substrate having adiameter of 120 mm and a thickness of 1.2 mm by use of M35-D-DM of MEIKICO., LTD.

(Optical Disk)

On the disk substrate, a reflective film, a first dielectric layer, aphase change recording film and a second dielectric layer were depositedin turn by sputtering, and a thin polycarbonate film cover layer waslaminated thereon so as to obtain an optical disk of interest. Theinitial mechanical properties, ΔTilt and damping of the disk substratewere evaluated. The results of the evaluations are shown in Table 5.

Example 20

(Polymerization)

White powder having a molar ratio of BCF/BPM of 35:65 was obtained inthe same manner as in Example 19 except that blowing of phosgene wascarried out by use of 1,814 parts of BCF used in Example 19 and 3,084parts of BPM used in Example 19 and 86 parts of p-t-butyl phenol wasadded after the blowing of phosgene. This powder had a specificviscosity of 0.283.

To this powder, the same additives as used in Example 19 were added inthe same amounts as used in Example 19, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 19. Then,the pellet was injection molded in the same manner as in Example 19 soas to obtain an optical disk.

(Optical Disk)

On the disk substrate, a reflective film, a first dielectric layer, aphase change recording film and a second dielectric layer were depositedin turn by sputtering, and a thin polycarbonate film cover layer waslaminated thereon so as to obtain an optical disk of interest. Theinitial mechanical properties, ΔTilt and damping of the disk substratewere evaluated. The results of the evaluations are shown in Table 5.

Example 21

(Polymerization)

White powder having a molar ratio of BCF/BPM of 50:50 was obtained inthe same manner as in Example 19 except that blowing of phosgene wascarried out by use of 2,277 parts of BCF used in Example 19 and 2,084parts of BPM used in Example 19 and 74 parts of p-t-butyl phenol wasadded after the blowing of phosgene. This powder had a specificviscosity of 0.263.

To this powder, the same additives as used in Example 19 were added inthe same amounts as used in Example 19, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 19. Then,the pellet was injection molded in the same manner as in Example 19 soas to obtain a disk substrate.

(Optical Disk)

On the disk substrate, a reflective film, a first dielectric layer, aphase change recording layer and a second dielectric layer weredeposited in turn by sputtering, and a thin polycarbonate film coverlayer was laminated thereon so as to obtain an optical disk of interest.The initial mechanical properties, ΔTilt and damping of the disksubstrate were evaluated. The results of the evaluations are shown inTable 5.

Example 22

(Polymerization)

White powder having a molar ratio of BCF/BPM/THPE of 40:60:0.5 wasobtained in the same manner as in Example 19 except that 23 parts ofTHPE and 81 parts of p-t-butyl phenol were added after blowing ofphosgene in Example 19. This powder had a specific viscosity of 0.283.

To this powder, the same additives as used in Example 19 were added inthe same amounts as used in Example 19, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 19. Then,the pellet was injection molded in the same manner as in Example 19 soas to obtain a disk substrate.

(Optical Disk)

On the disk substrate, a reflective film, a first dielectric layer, aphase change recording layer and a second dielectric layer weredeposited in turn by sputtering, and a thin polycarbonate film coverlayer was laminated thereon so as to obtain an optical disk of interest.The initial mechanical properties, ΔTilt and damping of the disksubstrate were evaluated. The results of the evaluations are shown inTable 5.

Example 23

(Polymerization)

White powder having a molar ratio of BCF/BPC of 40:60 was obtained inthe same manner as in Example 19 except that blowing of phosgene wascarried out by use of 2,277 parts of BCF used in Example 19 and 2,313parts of 2,2-bis(3-methyl-4-hydroxyphenyl)propane (hereinafter may beabbreviated as “BPC”) in place of BPM used in Example 19 and 72 parts ofp-t-butyl phenol was added after the blowing of phosgene. This powderhad a specific viscosity of 0.279.

To this powder, the same additives as used in Example 19 were added inthe same amounts as used in Example 19, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 19. Then,the pellet was injection molded in the same manner as in Example 19 soas to obtain a disk substrate.

(Optical Disk)

On the disk substrate, a reflective film, a first dielectric layer, aphase change recording layer and a second dielectric layer weredeposited in turn by sputtering, and a thin polycarbonate film coverlayer was laminated thereon so as to obtain an optical disk of interest.The initial mechanical properties, ΔTilt and damping of the disksubstrate were evaluated. The results of the evaluations are shown inTable 5.

Comparative Example 8

(Polymerization)

4,750 parts of colorless polymer was obtained in the same manner as inExample 19 except that only 4,320 parts of bisphenol A (BPA) was used asa dihydroxy component. This powder had a specific viscosity of 0.289.

To this powder, the same additives as used in Example 19 were added inthe same amounts as used in Example 19, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 19. Then,the pellet was injection molded in the same manner as in Example 19 soas to obtain a disk substrate.

(Optical Disk)

On the disk substrate, a reflective film, a first dielectric layer, aphase change recording layer and a second dielectric layer weredeposited in turn by sputtering, and a thin polycarbonate film coverlayer was laminated thereon so as to obtain an optical disk of interest.The initial mechanical properties, ΔTilt and damping of the disksubstrate were evaluated. The results of the evaluations are shown inTable 5.

Comparative Example 9

A disk substrate having a diameter of 120 mm and a thickness of 1.2 mmwas injection molded from a polymethyl methacrylate (VLD-100) of Rohm &Haas Japan Co., Ltd. by use of M35B-D-DM of MEIKI CO., LTD. On the disksubstrate, a reflective film, a first dielectric layer, a phase changerecording layer and a second dielectric layer were deposited in turn bysputtering, and a thin polycarbonate film cover layer was then laminatedthereon so as to obtain an optical disk of interest.

The initial mechanical properties, ΔTilt and damping of the disksubstrate were evaluated. The results of the evaluations are shown inTable 5.

As shown in Table 5, the resins shown in Examples 19 to 23 can reducesaturated water absorption to 0.3% or lower and ΔTilt to 0.5 or smaller.In addition, they also have sufficiently high flexural moduli and tan δ,surface swing occurring when the molded optical disks spin at high speedcan be kept small.

PC-A of Comparative Example 8 has low rigidity and tan δ. Hence, surfaceswing occurring when the optical disk spins at high speed is severe.Further, since it also has higher saturated water absorption thanExamples, its ΔTilt is large.

PMMA of Comparative Example 9 has a high saturated water absorption of2.0% or higher. Thus, its ΔTilt is very large as 5.0 or higher, and ithas been therefore found that it is not suitable for practical use.

TABLE 5 Ex. 19 Ex. 20 Ex. 21 Ex. 22 Ex. 23 C. Ex. 8 C. Ex. 9 CompositionBCF Component a 40 35 50 40 40 — — Ratio Bisphenol Fluorene — — — — — —— (mol %) BPM Component b 60 65 50 60 — — — BPC Component b — — — — 60 —— THPE — — — 0.5 — — — BPA 100 PMMA — — — — — — 100 Results of SpecificViscosity — 0.283 0.284 0.274 0.283 0.279 0.289 — Evaluations ofDeflection Temperature (° C.) 134 129 149 134 145 126 89 Resins underLoad tanδ — 0.039 0.037 0.042 0.039 0.032 0.007 0.078 Flexural Modulus(MPa) 3,100 3,040 3,170 3,170 2,910 2,400 3,630 Saturated Water wt %0.26 0.26 0.23 0.25 0.22 0.37 2.00 Absorption Results of CylinderTemperature (° C.) 320 Evaluations of Mold Tightening Force ton  32Disks Mold Temperature (° C.) 127 122 140 126 136 119 81 InitialSubstrate (degree) 0.20 0.20 0.20 0.20 0.20 0.20 0.36 Shape ΔTilt(degree) 0.46 0.46 0.42 0.46 0.43 0.78 5.00 or Larger Ex.: Example, C.Ex.: Comparative Example

Examples 24 to 31 and Comparative Examples 10 to 13 Plastic Mirror

Physical properties were measured by the following methods.

-   (1) Specific Viscosity: This is measured at a temperature of 20° C.    after 0.7 g of polymer is dissolved in 100 ml of methylene chloride.-   (2) Glass Transition Point (Tg): This is measured at a temperature    increasing rate of 10° C./min by use of the 2910 type DSC of TA    INSTRUMENTS JAPAN CO., LTD.-   (3) Water Absorption: Water absorption after immersed in water at    23° C. for 24 hours is measured in accordance with ISO62.-   (4) Flexural Modulus: The flexural modulus of a test piece prepared    by drying a pellet at 120° C. for 5 hours and then subjecting the    pellet to injection molding at a cylinder temperature of 300° C. by    use of an injection molding machine (SG-150 of Sumitomo Heavy    Industries, Ltd.) is measured in accordance with ISO178.-   (5) Degree of Warpage: A disk substrate having a diameter of 120 mm    and a thickness of 1.2 mm is injection molded by use of M35B-D-DM of    MEIKI CO., LTD. Thereafter, an aluminum film is deposited on one    surface of the substrate. After the disk substrate is exposed to an    environment (environment A) where the temperature is 30° C. and the    humidity is 90% RH until reaching saturated water absorption, the    disk substrate is transferred to an environment (environment B)    where the temperature is 23° C. and the humidity is 50% RH. After    the transfer, a tilt change at 58 mm from the center which occurs    due to the change of the environment is measured with time by use of    the three dimensional shape measuring device DLD-3000U of Japan EM    Co., Ltd. The difference between the maximum value of the tilt    change and a value at which the tilt change is settled is taken as    ΔTilt.-   (6) Mold Printability: The surface roughness of a molded substrate    is measured by use of SURFCORDER SE1100 of Kosaka laboratory Ltd.

Example 24

(Polymerization)

To a reactor equipped with a thermometer and agitator, 19,580 parts ofion exchange water and 3,850 parts of 48.5% sodium hydroxide aqueoussolution were added, and 1,175 parts of BCF, 2,835 parts of2,2-bis(4-hydroxyphenyl)propane (hereinafter may be abbreviated as“BPA”) and 9 parts of hydrosulfite were then dissolved. Then, after13,210 parts of methylene chloride was added, 2,000 parts of phosgenewas blown into the mixture at 15° C. in about 40 minutes under vigorousagitation so as to cause a reaction. After completion of the blowing ofphosgene, the temperature was raised to 28° C., and 94 parts ofp-t-butyl phenol and 640 parts of sodium hydroxide were added so as tocause emulsification. Then, 6 parts of triethylamine was added, and theresulting mixture was continuously agitated for 1 hour, therebycompleting the reaction.

After completion of the reaction, the organic phase was separated,diluted with methylene chloride, washed with water, made acidic byhydrochloric acid and then washed with water. When the electricconductivity of the water phase became nearly the same as that of ionexchange water, methylene chloride was evaporated by a kneader. Thereby,4,080 parts of colorless powder having a molar ratio of BCF/PCA of 20:80was obtained. This powder had a specific viscosity of 0.285 and a Tg of172° C.

(Molding)

To this powder, 0.003 parts of tris(2,4-di-t-butylpyhenyl)phosphite,0.005 parts of trimethyl phosphate and 0.045 parts of monoglyceridestearate were added based on 100 parts of the powder. Then, the powderwas melt-kneaded by use of a vented twin screw extruder (KTX-46 of KobeSteel, Ltd.) at a cylinder temperature of 280° C. while being deaerated,pelletized, and then injection molded into a disk substrate having adiameter of 120 mm and a thickness of 1.2 mm by use of M35B-D-DM ofMEIKI CO., LTD. The substrate had a sufficiently smooth surface so as tobe used for a plastic mirror.

Further, on the substrate, aluminum was deposited to a thickness of 50nm by use of the EKC-1 Ion Plating apparatus of Sumitomo HeavyIndustries, Ltd. The maximum warpage of the aluminum deposited substrateby absorption of water was 0.9 deg. Further, the substrate also showed awater absorption of 0.170 wt % and a flexural modulus of 2,700 MPa.

Example 25

(Polymerization)

4,830 parts of colorless powder having a molar ratio of BCF/BPA of 50:50was obtained in the same manner as in Example 24 except that 2,937 partsof BCF, 1,772 parts of BPA and 84 parts of p-t-butyl phenol were used.This powder had a specific viscosity of 0.278 and a Tg of 195° C.

(Molding)

To this powder, the same additives as used in Example 24 were added inthe same amounts as used in Example 24, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 24 exceptthat the cylinder temperature was 300° C. Then, this pellet wasinjection molded in the same manner as in Example 24 so as to obtain asubstrate. The substrate had a sufficiently smooth surface so as to beused for a plastic mirror.

On the substrate, aluminum was deposited. The maximum warpage of thealuminum deposited substrate by absorption of water was 0.9 deg.Further, the substrate also showed a water absorption of 0.160 wt % anda flexural modulus of 2,950 MPa.

Example 26

(Polymerization)

4,050 parts of colorless powder having a molar ratio of BCF/BPA/THPE of20:80:0.5 was obtained in the same manner as in Example 24 except that24 parts of 1,1,1-tris(4-hydroxyphenyl)ethane (hereinafter may beabbreviated as “THPE”) was added after blowing of phosgene and theamount of p-t-butyl phenol was changed to 104 parts. This powder had aspecific viscosity of 0.285 and a Tg of 173° C.

(Molding)

To this powder, the same additives as used in Example 24 were added inthe same amounts as used in Example 24, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 24. Then,this pellet was injection molded in the same manner as in Example 24 soas to obtain a substrate. The substrate had a sufficiently smoothsurface so as to be used for a plastic mirror.

On the substrate, aluminum was deposited. The maximum warpage of thealuminum deposited substrate by absorption of water was 0.9 deg.Further, the substrate also showed a water absorption of 0.160 wt % anda flexural modulus of 2,720 MPa.

Example 27

(Polymerization)

5,300 parts of colorless powder having a molar ratio of BCF/BPA of 70:30was obtained in the same manner as in Example 24 except that 4,112 partsof BCF, 1,063 parts of BPA and 84 parts of p-t-butyl phenol were used.This powder had a specific viscosity of 0.261 and a Tg of 210° C.

(Molding)

To this powder, the same additives as used in Example 24 were added inthe same amounts as used in Example 24, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 24 exceptthat the cylinder temperature was 320° C. Then, this pellet wasinjection molded in the same manner as in Example 24 so as to obtain asubstrate. The substrate had a sufficiently smooth surface so as to beused for a plastic mirror.

On the substrate, aluminum was deposited. The maximum warpage of thealuminum deposited substrate by absorption of water was 0.9 deg.Further, the substrate also showed a water absorption of 0.150 wt % anda flexural modulus of 3,200 MPa.

Comparative Example 10

(Polymerization)

3,670 parts of colorless polymer was obtained in the same manner as inExample 24 except that only 3,543 parts of BPA was used as a dihydroxycomponent and 140 parts of p-t-butyl phenol was used. This powder had aspecific viscosity of 0.290 and a Tg of 142° C.

(Molding)

To this powder, the same additives as used in Example 24 were added inthe same amounts as used in Example 24, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 24. Then,this pellet was injection molded in the same manner as in Example 24 soas to obtain a substrate. The substrate had a sufficiently smoothsurface so as to be used for a plastic mirror. Then, on the substrate,aluminum was deposited. The maximum warpage of the aluminum depositedsubstrate by absorption of water was 1.4 deg. Further, the substratealso showed a high water absorption of 0.21 wt % and a low flexuralmodulus of 2,350 MPa.

Comparative Example 11

(Polymerization)

3,650 parts of colorless polymer was obtained in the same manner as inExample 24 except that only 3,542 parts of BPA was used as a dihydroxycomponent and 140 parts of p-t-butyl phenol was used. This powder has aspecific viscosity of 0.289 and a Tg of 142° C.

(Molding)

To this powder, the same additives as used in Example 24 were added inthe same amounts as used in Example 24, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 24.Further, to this resin, 1,188 parts of glass fibers having a fiberdiameter of 13 microns of Nippon Electric Glass Co., Ltd. were added.After they were mixed uniformly by a tumbler, the mixture wasmelt-kneaded at 240° C. by a vented twin screw extruder (KTX-46 of KobeSteel, Ltd.) while being deaerated so as to obtain a pellet. Then, adisk substrate having a diameter of 120 mm and a thickness of 1.2 mm wasinjection molded from the pellet by use of M35B-D-DM of MEIKI CO., LTD.Further, on the substrate, aluminum was deposited to a film thickness of50 nm by use of the EKC-1 Ion Plating apparatus of Sumitomo HeavyIndustries, Ltd. Although the aluminum deposited substrate showed asignificantly improved rigidity of 6,330 MPa, some of the glass fibersappeared on the surface of the substrate, thereby making the substrateimpossible to use as a mirror. Further, the aluminum deposited substrateshowed a water absorption of 0.13 wt % and a maximum warpage byabsorption of water of 0.1 deg.

The results of these Examples and Comparative Examples are shown inTable 6.

(Polygon Mirror)

Further, the pellets obtained in the above Examples 24 to 27 andComparative Examples 10 and 11 were dried at 120° C. for 5 hours. Then,hexahedral mirror type polygon mirror substrates each having a distancebetween the center and each mirror surface of 25 mm, a minimum platethickness in each mirror portion of 5 mm and a height of the mirrorportion of 15 mm were molded by use of an injection molding machine(SG150U of Sumitomo Heavy Industries, Ltd.) at a cylinder temperature of340° C. and a mold temperature of 115° C. The results of evaluations ofthe mold printabilities of the polygon mirrors are shown in Table 6.

Then, on these substrates, an Al film was deposited to a thickness of 80nm so as to prepare polygon mirrors. Comparative Example 11 could not beused as a mirror since it had poor surface properties. ComparativeExample 10 had an insufficient flexural modulus, and distortions inmirror portions by rotations were severe. Examples 24 to 27 had goodsurface properties, had small distortions in mirror portions due to highflexural moduli and were therefore sufficiently practicable.

TABLE 6 Item Ex. 24 Ex. 25 Ex. 26 Ex. 27 C. Ex. 10 C. Ex. 11 BCFComponent a 20 50 20 70 — — BPA Component b 80 50 80 30 100 100 THPE — —0.5 — — — Glass Fibers — — — — — 25 Specific Viscosity — 0.285 0.2780.285 0.261 0.290 0.289 Glass Transition Temperature (° C.) 172 195 173210 142 142 Flexural Modulus (MPa) 2,700 2,950 2,720 3,200 2,350 6,330Water Absorption wt % 0.170 0.160 0.160 0.150 0.210 0.130 CylinderTemperature (° C.) 320 340 320 350 280 280 Mold Tightening Force (ton)65 65 65 65 65 65 Mold Temperature (° C.) 100 130 100 130 100 100Maximum Warpage by Absorption (deg) 0.9 0.9 0.9 0.9 1.4 0.1 of WaterSurface Disk nm 40 50 45 51 30 600 Roughness Polygon Mirror Substrate nm38 50 48 45 32 570 Ex.: Example, C. Ex.: Comparative Example

Example 28

(Polymerization)

To a reactor equipped with a thermometer, agitator, reflux condenser andphosgene blowing tube, 32,165 parts of ion exchange water and 1,757parts of sodium hydroxide were added, and 2,213 parts of9,9-bis(3-methyl-4-hydroxyphenyl)fluorene (hereinafter may beabbreviated as “BCF”), 3,039 parts of4,4′-(m-phenylenediisopropylidene)diphenol (hereinafter may beabbreviated as “BPM”) and 11 parts of hydrosulfite were dissolved. Then,after 10,950 parts of methylene chloride was added, 1,667 parts ofphosgene was blown into the mixture at 16 to 18° C. in 60 minutes underagitation. After completion of the blowing of phosgene, 92 parts ofp-t-butyl phenol and 293 parts of sodium hydroxide were added, 4 partsof triethylamine was further added, and the resulting mixture wasagitated at 30° C. for 1 hour, thereby completing the reaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. Thereby, 5,554 parts of colorlesspowder having a molar ratio of BCF/BPM of 40:60 was obtained. Thispowder had a specific viscosity of 0.285 and a Tg of 144° C.

(Molding)

To this powder, 0.003 parts of tris(2,4-di-t-butylpyhenyl)phosphite,0.00.5 parts of trimethyl phosphate and 0.045 parts of monoglyceridestearate were added based on 100 parts of the powder.

Then, the powder was melt-kneaded by use of a vented twin screw extruder(KTX-46 of Kobe Steel, Ltd.) at a cylinder temperature of 240° C. whilebeing deaerated, pelletized, and then injection molded into a disksubstrate having a diameter of 120 mm and a thickness of 1.2 mm by useof M35B-D-DM of MEIKI CO., LTD. The substrate had a sufficiently smoothsurface so as to be used for a plastic mirror.

Further, on the substrate, aluminum was deposited to a thickness of 50nm by use of the EKC-1 Ion Plating apparatus of Sumitomo HeavyIndustries, Ltd. The maximum warpage of the aluminum deposited substrateby absorption of water was 0.4 deg. Further, the substrate showed an MVRof 34 g/10 min, a water absorption of 0.083 wt % and a flexural modulusof 3,260 MPa.

Example 29

(Polymerization)

5,224 parts of colorless powder having a molar ratio of BCF/BPM of 50:50was obtained in the same manner as in Example 28 except that 2,596 partsof BCF and 2,377 parts of BPM were used. This powder had a specificviscosity of 0.269 and a Tg of 155° C.

(Molding)

To this powder, the same additives as used in Example 28 were added inthe same amounts as used in Example 28, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 28. Then,this pellet was injection molded in the same manner as in Example 28 soas to obtain a substrate. The substrate had a sufficiently smoothsurface so as to be used for a plastic mirror. Then, on the substrate,aluminum was deposited. The maximum warpage of the aluminum depositedsubstrate by absorption of water was 0.4 deg. Further, the substrateshowed an MVR of 26 g/10 min, a water absorption of 0.080 wt % and aflexural modulus of 3,330 MPa.

Example 30

(Polymerization)

5,245 parts of colorless powder having a molar ratio of BCF/BPM/THPE of40:60:0.5 was obtained in the same manner as in Example 28 except that21 parts of 1,1,1,-tris(4-hydroxxyphenyl)ethane (hereinafter may beabbreviated as “THPE”) was further added after blowing of phosgene andthe amount of p-t-butyl phenol was changed to 113 parts. This powder hada specific viscosity of 0.288 and a Tg of 143° C.

(Molding)

To this powder, the same additives as used in Example 28 were added inthe same amounts as used in Example 28, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 28. Then,this pellet was injection molded in the same manner as in Example 28 soas to obtain a substrate. The substrate had a sufficiently smoothsurface so as to be used for a plastic mirror. Then, on the substrate,aluminum was deposited. The maximum warpage of the aluminum depositedsubstrate by absorption of water was 0.4 deg. Further, the substrateshowed an MVR of 36 g/10 min, a water absorption of 0.083 wt % and aflexural modulus of 3,280 MPa.

Example 31

(Polymerization)

5,460 parts of colorless powder having a molar ratio of BCF/BPM of 65:35was obtained in the same manner as in Example 28 except that 3,598 partsof BCF and 1,773 parts of BPM were used. This powder had a specificviscosity of 0.264 and a Tg of 175° C.

(Molding)

To this powder, the same additives as used in Example 28 were added inthe same amounts as used in Example 28, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 28 exceptthat the cylinder temperature was 280° C. Then, this pellet wasinjection molded in the same manner as in Example 28 so as to obtain asubstrate. The substrate had a sufficiently smooth surface so as to beused for a plastic mirror. Then, on the substrate, aluminum wasdeposited. The maximum warpage of the aluminum deposited substrate byabsorption of water was 0.5 deg. Further, the substrate showed an MVR of26 g/10 min, a water absorption of 0.080 wt % and a flexural modulus of3,330 MPa.

Comparative Example 12

(Polymerization)

4,750 parts of colorless polymer was obtained in the same manner as inExample 28 except that only 4,320 parts of bisphenol A was used as adihydroxy component. This powder had a specific viscosity of 0.289 and aTg of 142° C.

(Molding)

To this powder, the same additives as used in Example 28 were added inthe same amounts as used in Example 28, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 28. Then,this pellet was injection molded in the same manner as in Example 28 soas to obtain a substrate. The substrate had a sufficiently smoothsurface so as to be used for a plastic mirror. Then, on the substrate,aluminum was deposited. The maximum warpage of the aluminum depositedsubstrate by absorption of water was as large as 1.4 deg. Further, thesubstrate showed an MVR of 69 g/10 min, a high water absorption of 0.21wt % and a low flexural modulus of 2,350 MPa.

Comparative Example 13

(Polymerization)

4,750 parts of colorless polymer was obtained in the same manner as inExample 28 except that only 4,320 parts of bisphenol A was used as adihydroxy component. This powder had a specific viscosity of 0.286 and aTg of 142° C.

(Molding)

To this powder, the same additives as used in Example 28 were added inthe same amounts as used in Example 28, and the resulting mixture wasmelt-kneaded and pelletized in the same manner as in Example 28.Further, to this resin, 1,188 parts of glass fibers having a fiberdiameter of 13 microns of Nippon Electric Glass Co., Ltd. were added.After they were mixed uniformly by a tumbler, the mixture wasmelt-kneaded at 240° C. by a vented twin screw extruder (KTX-46 of KobeSteel, Ltd.) while being deaerated so as to obtain a pellet. Then, adisk substrate having a diameter of 120 mm and a thickness of 1.2 mm wasinjection molded from the pellet by use of M35B-D-DM of MEIKI CO., LTD.Further, on the substrate, aluminum was deposited to a film thickness of50 nm by use of the EKC-1 Ion Plating apparatus of Sumitomo HeavyIndustries, Ltd. Although the aluminum deposited substrate showed asignificantly improved rigidity of 6,330 MPa, some of the glass fibersappeared on the surface of the substrate, thereby making the substrateimpossible to use as a mirror. Further, the aluminum deposited substrateshowed an MVR of 64 g/10 min, a water absorption of 0.13 wt % and amaximum warpage by absorption of water of 0.1 deg.

The results of these Examples and Comparative Examples are shown inTable 7.

(Polygon Mirror)

Further, the pellets obtained in the above Examples 28 to 31 andComparative Examples 12 and 13 were dried at 120° C. for 5 hours. Then,hexahedral mirror type polygon mirror substrates each having a distancebetween the center and each mirror surface of 25 mm, a minimum platethickness in each mirror portion of 5 mm and a height of the mirrorportion of 15 mm were molded by use of an injection molding machine(SG150U of Sumitomo Heavy Industries, Ltd.) at a cylinder temperature of300° C. and a mold temperature of 100° C. The results of evaluations ofthe mold printabilities of the polygon mirrors are shown in Table 7.

Then, on these substrates, an Al film was deposited to a thickness of 80nm so as to prepare polygon mirrors. Comparative Example 12 could not beused as a mirror since it had poor surface properties. ComparativeExample 12 had an insufficient flexural modulus, and distortions inmirror portions by rotations were severe. Examples 28 to 31 had goodsurface properties, had small distortions in mirror portions due to highflexural moduli and were therefore sufficiently practicable.

TABLE 7 Item Ex. 28 Ex. 29 Ex. 30 Ex. 31 C. Ex. 12 C. Ex. 13 BCFComponent a 40 50 40 65 — — BPM Component b 60 50 60 35 — — BPA — — — —100 100 THPE — — 0.5 — — — Glass Fibers — — — — — 25 Specific Viscosity— 0.285 0.269 0.288 0.264 0.289 0.286 Glass Transition Temperature (°C.) 144 155 143 175 142 142 Flexural Modulus (MPa) 3,260 3,330 3,2803,520 2,350 6,330 Water Absorption wt % 0.083 0.080 0.083 0.079 0.2100.130 MVR cm³ 34 26 36 9 69 64 Cylinder Temperature (° C.) 280 280 280320 280 280 Mold Tightening Force (ton) 65 65 65 65 65 65 MoldTemperature (° C.) 100 100 100 120 100 100 Maximum Warpage by Absorption(deg) 0.4 0.4 0.4 0.5 1.4 0.1 of Water Surface Disk nm 30 35 35 34 30600 Roughness Polygon Mirror Substrate nm 32 34 36 35 32 570 Ex.:Example, C. Ex.: Comparative Example

Examples 32 to 36 and Comparative Examples 14 and 15 Conductive ResinComposition

Physical properties were evaluated by the following methods.

(1) Specific Viscosity

This is measured at a temperature of 20° C. after 0.7 g of polymer isdissolved in 100 ml of methylene chloride.

(2) Glass Transition Point (Tg)

This is measured at a temperature increasing rate of 20° C./min by useof the 2910 type DSC of TA INSTRUMENTS JAPAN CO., LTD.

(3) Heat Resistance

A deflection temperature under a load of 18.5 kg is measured inaccordance with ASTM D648.

(4) Electric Conductivity

A surface resistivity value is measured in accordance with ASTM D257.

(5) Water Absorption

Water absorption after immersed in water at 23° C. for 24 hours ismeasured in accordance with ASTM D-0570.

(6) Irritation

A polymer which causes irritation to skin is evaluated as “x” and apolymer which causes no irritation to skin is evaluated as “◯” duringformation of molded pieces to be measured by the following methods.

(7) Heat Cycle Test

A injection molded carrying tray having a size of 153 mm×142 mm×165 mmand a groove pitch of 4.76 mm and capable of holding 25 5-inch disks issubjected to 10 cycles each of which comprises 20 hours at 150° C. and 4hours at 23° C., and the occurrence of distortion in the molded articlewas observed.

(Polymerization)

PC1

To a reactor equipped with a thermometer, agitator and reflux condenser,21,538 parts of ion exchange water and 4,229 parts of 48% sodiumhydroxide aqueous solution were added, and 1,949 parts of bisphenol A,3,231 parts of biscresolfluorene and 10.9 parts of hydrosulfite weredissolved. Then, after 14,530 parts of methylene chloride was added,2,200 parts of phosgene was blown into the mixture at 16 to 20° C. in 60minutes under agitation. After completion of the blowing of phosgene,115.4 parts of p-t-butyl phenol and 705 parts of 48% sodium hydroxideaqueous solution were added, 2.6 parts of triethylamine was furtheradded, and the resulting mixture was agitated at 20 to 27° C. for 40minutes, thereby completing the reaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. As a result, 5,520 parts ofwhitish yellow polymer having a molar ratio of bisphenolA/biscresolfluorene of 50:50, a specific viscosity of 0.272 and a Tg of197° C. was obtained (yield: 96%).

To this polycarbonate copolymer, 0.050% oftris(2,4-di-t-butylphenyl)phosphite, 0.010% ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 0.030% ofpentaerythritol tetrastearate were added, and the resulting mixture wasextruded by an extruder at a cylinder temperature of 300° C. so as toobtain a polycarbonate copolymer pellet (PC1).

PC2

To a reactor equipped with a thermometer, agitator and reflux condenser,19,580 parts of ion exchange water and 3,845 parts of 48% sodiumhydroxide aqueous solution were added, and 2,835 parts of bisphenol A,1,175 parts of biscresolfluorene and 8.4 parts of hydrosulfite weredissolved. Then, after 13,209 parts of methylene chloride was added,2,000 parts of phosgene was blown into the mixture at 18 to 20° C. in 60minutes under agitation. After completion of the blowing of phosgene,93.2 parts of p-t-butyl phenol and 641 parts of 48% sodium hydroxideaqueous solution were added, 2.0 parts of triethylamine was furtheradded, and the resulting mixture was agitated at 20 to 27° C. for 40minutes, thereby completing the reaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. As a result, 4,230 parts ofwhitish yellow polymer having a molar ratio of bisphenolA/biscresolfluorene of 80:20, a specific viscosity of 0.374 and a Tg of173° C. was obtained (yield: 94%).

To this polycarbonate copolymer, 0.050% oftris(2,4-di-t-butylphenyl)phosphite, 0.010% ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 0.030% ofpentaerythritol tetrastearate were added, and the resulting mixture wasextruded by an extruder at a cylinder temperature of 280° C. so as toobtain a polycarbonate copolymer pellet (PC2).

To a reactor equipped with a thermometer, agitator and reflux condenser,20,980 parts of ion exchange water and 1,523 parts of potassiumhydroxide were added, and 886 parts of bisphenol A, 1,360 parts of9,9-bis(4-hydroxyphenyl)fluorene (hereinafter referred to as“bisphenolfluorene”) and 4.7 parts of hydrosulfite were dissolved. Then,after 13,210 parts of methylene chloride was added, 1,000 parts ofphosgene was blown into the mixture at 18 to 20° C. in 60 minutes underagitation. After completion of the blowing of phosgene, 52.4 parts ofp-t-butyl phenol and 218 parts of potassium hydroxide were added, 2.7parts of triethylamine was further added, and the resulting mixture wasagitated at 20 to 27° C. for 40 minutes, thereby completing thereaction.

After completion of the reaction, the obtained product was diluted withmethylene chloride, washed with water, made acidic by hydrochloric acidand then washed with water. When the electric conductivity of the waterphase became nearly the same as that of ion exchange water, methylenechloride was evaporated by a kneader. As a result, 2,250 parts ofwhitish yellow polymer having a molar ratio of bisphenolA/bisphenolfluorene of 50:50, a specific viscosity of 0.272 and a Tg of205° C. was obtained (yield: 90%).

To this polycarbonate copolymer, 0.050% oftris(2,4-di-t-butylphenyl)phosphite, 0.010% ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 0.030% ofpentaerythritol tetrastearate were added, and the resulting mixture wasextruded by an extruder at a cylinder temperature of 300° C. so as toobtain a polycarbonate copolymer pellet (C-PC1).

C-PC2

3,870 parts of whitish yellow polymer having a molar ratio of bisphenolA/biscresolfluorene of 9.9:1, a specific viscosity of 0.390 and a Tg of148° C. was obtained (yield: 95%) in the same manner as in production ofPC1 except that 3,907 parts of bisphenol A and 59 parts ofbiscresolfluorene were used. An aromatic polycarbonate resin pellet(C-PC2) was obtained from the polymer in the same manner as in theproduction of PC1.

(Carbon Based Filler)

Carbon Fiber: BESFIGHT HTA-C6-U of TOHO RAYON CO., LTD., PAN based,epoxy converged, fiber diameter of 7 microns Carbon Black: ketjenblackEC600JD of Lion Corporation (hereinafter referred to as “CB”)

Examples 32 to 36 and Comparative Examples 14 and 15

(Molding)

The above obtained PC1 and PC2, C-PC1 or C-PC2, and components shown inTables 8 and 9 were mixed uniformly by use of a tumbler and thenpelletized by use of a φ30-mm vented twin screw extruder (KTX-30 of KobeSteel, Ltd.) at a cylinder temperature of 300° C. and a degree of vacuumof 10 mmHg while being deaerated. The obtained pellets were dried at120° C. for 5 hours, and molded pieces to be measured were then preparedby use of an injection molding machine (SG150U of Sumitomo HeavyIndustries, Ltd.) at a cylinder temperature of 330° C. and a moldtemperature of 100° C. The results of evaluations are shown in Tables 8and 9.

(Carrying Tray)

Further, after pellets prepared in the same manner as described abovewere dried at 120° C. for 5 hours, carrying trays each having a size of153 mm×142 mm×165 mm and a groove pitch of 4.76 mm and capable ofholding 25 5-inch disks were injection molded at a cylinder temperatureof 350° C. and a mold temperature of 100° C. The results of heat cycletests are shown in Tables 8 and 9.

It is obvious from comparisons among the above Examples and ComparativeExamples that aromatic polycarbonate resin compositions comprising thepolycarbonate copolymers of the present invention and the carbon fibershave better heat resistance and conductivity than the compositions ofComparative Examples using the aromatic polycarbonate resins and causeno irritation to skin.

TABLE 8 Unit Ex. 32 Ex. 33 Ex. 34 Ex. 35 Ex. 36 CompositionsPolycarbonate Resins PC1 Parts by Weight 100 100 100 100 PC2 Parts byWeight 100 Carbon Based Fillers Carbon Fibers Parts by Weight  20  20 12  10 CB Parts by Weight  10  1 Evaluations Deflection Temperatureunder Load ° C. 192 171 191 186 189 Conductivity Ω  10⁴  10⁴  10⁵  10³ 10³ Water Absorption % by Weight  0.16  0.18  0.17  0.18  0.17Irritation — ◯ ◯ ◯ ◯ ◯ Heat Cycle Test — Good Good Good Good Good Ex.:Example

TABLE 9 Unit C. Ex. 14 C. Ex. 15 Compositions Polycarbonate Resins PC1Parts by Weight PC2 Parts by Weight C-PC1 Parts by Weight 100 C-PC2Parts by Weight 100 Carbon Based Fillers Carbon Fibers Parts by Weight 20  20 CB Parts by Weight Evaluations Deflection Temperature under Load° C. 195 147 Conductivity Ω  10⁴  10⁴ Water Absorption % by Weight  0.26 0.20 Irritation — X ◯ C. Ex.: Comparative Example

According to the present invention, there is provided a polycarbonatecopolymer having excellent heat resistance and dimensional stability andlow water absorption and causing no irritation to skin. Further,according to the present invention, heat resistant parts comprising thecopolymer and suitable for various applications are provided.

The part for reflow soldering of the present invention has excellenttransparency and heat resistance and undergoes no deformation even aftertreated in a reflow furnace showing a peak temperature of 250° C. Thus,it can be used as a part to be incorporated into a substrate by reflowsoldering, e.g., a camera lens of a camera-incorporated mobiletelephone.

The light path converting part of the present invention has good heatresistance and thermal stability, a very little birefringence andexcellent transparency. Thus, it is suitable for use as a pickup lens, acamera lens, a microarray lens, a projector lens or a prism.

The optical disk of the present invention has excellent rigidity,damping, heat resistance and water absorbability and is suitable for useas a recording medium having a high density recording capacity.

The plastic mirror of the present invention has high rigidity andexcellent dimensional stability and mold printability at the time ofmolding. Thus, it is suitable for use as a polygon mirror, a projectormirror or the like.

The conductive resin composition of the present invention has anadvantage that it has good heat resistance, excellent conductivity andlow water absorption and causes no irritation to skin. Thus, it issuitable for use as a carrying tray for electronic parts such as asemiconductor, an optical data recording medium or a hard disk.

POSSIBILITY OF INDUSTRIAL UTILIZATION

The polycarbonate copolymer of the present invention can be applied tooptical components requiring heat resistance, transparency anddimensional stability, e.g., lenses, prisms, optical disks and plasticmirrors. In addition, it can also be used in a production process ofelectronic parts, e.g., as a carrying tray for the electronic parts.

1. A part for reflow soldering, the part comprising a polycarbonatecopolymer, the polycarbonate copolymer comprising 60 to 95 mol % ofrecurring unit (component a) represented by the following generalformula (I):

and 40 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II-1).


2. The part of claim 1, wherein the polycarbonate copolymer comprises 70to 85 mol % of the recurring unit represented by the general formula (I)and 30 to 15 mol % of the recurring unit represented by the generalformula (II-1).
 3. The part of claim 1, wherein the polycarbonatecopolymer shows a specific viscosity of 0.17 to 0.55 which is measuredat 20° C., dissolving 0.7 g of the copolymer in 100 ml of methylenechloride.
 4. The part of claim 1, wherein the polycarbonate copolymershows a glass transition temperature (Tg) of 200 to 250° C. which ismeasured at a temperature increasing rate of 20° C./min.
 5. The part ofclaim 1, which is a lens, lens barrel or prism.
 6. A light pathconverting part comprising a polycarbonate copolymer, the polycarbonatecopolymer comprising 5 to 95 mol % of recurring unit (component a)represented by the following general formula (I):

and 50 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).
 7. The part of claim 6, wherein thepolycarbonate copolymer comprises 50 to 95 mol % of the recurring unitrepresented by the general formula (I) and 50 to 5 mol % of therecurring unit represented by the general formula (II).
 8. The part ofclaim 6, wherein the polycarbonate copolymer comprises 5 to 95 mol % ofrecurring unit (component a) represented by the following generalformula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II-1) and/or (II-2).


9. The part of claim 6, wherein the polycarbonate copolymer shows atransmittance at 550 nm of 80% or higher as a molded plate and satisfiesthe following expression:Re ₅₅₀ /d≦10 when retardation at 550 nm is Re₅₅₀ (nm) and the thicknessof a portion where the transmittance and the retardation are measured isd (mm).
 10. The part of claim 6, which is a pickup lens, camera lens,microarray lens, projector lens or prism.
 11. An optical disk thatcomprises a substrate with a thickness of 0.3 to 1.2 mm which hasembossed pits or guide grooves, a reflective layer formed on thesubstrate and a transparent protective layer with a thickness of 3 to200 μm which is formed on the reflective layer and that reproducesrecorded data based on a change in the light intensity of reflectedlight produced by irradiating the disk with a light beam from thetransparent protective layer side, the substrate substantiallycomprising a polycarbonate copolymer, the polycarbonate copolymercomprising 20 to 95 mol % of recurring unit (component a) represented bythe following general formula (I):

 and 80 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

 (wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group), the substrate showing: (A) aflexural modulus of 2,800 to 4,000 MPa, (B) a water absorption of 0.3 wt% or lower upon reaching saturation, (C) a tan δ measured at 40° C. and18 Hz in accordance with ISO 6721-4 of at least 0.020, and (D) adeflection temperature under load measured under a load of 1.81 MPa inaccordance with ISO 75-1, -2 of 110° C. or higher.
 12. The disk of claim11, wherein the polycarbonate copolymer comprises 25 to 70 mol % of therecurring unit (component a) represented by the general formula (I) and75 to 30 mol % of the recurring unit (component b) represented by thegeneral formula (II).
 13. The disk of claim 11, wherein thepolycarbonate copolymer comprises 20 to 95 mol % of recurring unit(component a) represented by the following general formula (I):

and 80 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II-2) and/or (II-3).


14. The disk of claim 11, which has a recording layer between thereflective layer and the transparent protective layer.
 15. The disk ofclaim 11, wherein the embossed pits or the guide grooves are formed onboth surfaces of the substrate, and the reflective layer, the recordinglayer and/or the transparent protective layer are/is also formed on bothsurfaces thereof.
 16. The disk of claim 11, which has a multilayerstructure that the recording layer or the reflective layer is laminatedmultiple times.
 17. The disk of claim 11, wherein the polycarbonatecopolymer shows a specific viscosity measured at 20° C. of 0.1 to 0.5when 0.7 g of the copolymer is dissolved in 100 ml of methylenechloride.
 18. The disk of claim 11, wherein the transparent protectivelayer is composed of the same polycarbonate copolymer as thatconstituting the substrate.
 19. A plastic mirror which is a polygonmirror or projector mirror comprising a polycarbonate substrate and ametallic reflective film, the polycarbonate substrate comprising apolycarbonate copolymer, the polycarbonate copolymer comprising 20 to 70mol % of recurring unit (component a) represented by the followinggeneral formula (I):

 and 80 to 30 mol % of recurring unit (component b) represented by thefollowing general formula (II-1) and/or (II-2):

 the polycarbonate substrate showing: (A) a glass transition temperatureof 120 to 230° C., (B) a water absorption of 0.2 wt % or lower afterimmersed in water at 23° C. for 24 hours, and (C) a flexural modulus of2,500 to 4,000 MPa.
 20. The mirror of claim 19, wherein the molar ratioof the component a to the component b is 30:70 to 60:40.
 21. The mirrorof claim 19, wherein the polycarbonate copolymer comprises 20 to 70 mol% of the recurring unit (component a) represented by the general formula(I) and 80 to 30 mol % of the recurring unit (component b) representedby the general formula (II-1), and the polycarbonate substrate shows thefollowing properties, i.e., (A) a glass transition temperature of 160 to230° C., (B) a water absorption of 0.2 wt % or lower after immersed inwater at 23° C. for 24 hours, and (C) a flexural modulus of 2,500 to3,500 MPa.
 22. The mirror of claim 19, wherein the polycarbonatecopolymer comprises 20 to 70 mol % of the recurring unit (component a)represented by the general formula (I) and 80 to 30 mol % of therecurring unit (component b) represented by the general formula (II-2),and the polycarbonate substrate shows the following properties, i.e.,(A) a glass transition temperature of 120 to 180° C., (B) a waterabsorption of 0.1 wt % or lower after immersed in water at 23° C. for 24hours, and (C) a flexural modulus of 2,800 to 4,000 MPa.
 23. The mirrorof claim 19, wherein the polycarbonate copolymer shows a specificviscosity measured at 20° C. of 0.1 to 0.5 when 0.7 g of the copolymeris dissolved in 100 ml of methylene chloride.
 24. The mirror of claim19, wherein the polycarbonate copolymer shows an amount flown out in 10minutes at 300° C. and 1.2 kgf in an MVR measurement of not smaller than5 cm³.
 25. The mirror of claim 19, which has a spherical, non-spherical,flat or polyhedral shape.
 26. A conductive resin composition comprisinga polycarbonate copolymer and a carbon based filler, the polycarbonatecopolymer comprising 5 to 95 mol % of recurring unit (component a)represented by the following general formula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II):

(wherein R^(a) to R^(d) are each independently a hydrogen atom, ahydrocarbon group which may contain an aromatic group having 1 to 9carbon atoms or a halogen atom, and W is a single bond, a hydrocarbongroup which may contain an aromatic group having 1 to 20 carbon atoms oran O, S, SO, SO₂, CO or COO group).
 27. The composition of claim 26,which comprises 40 to 99 wt % of the polycarbonate copolymer and 60 to 1wt % of the carbon based filler.
 28. The composition of claim 26,wherein the polycarbonate copolymer comprises 5 to 95 mol % of recurringunit (component a) represented by the following general formula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II-1).


29. A tray for conveying an electronic part, the tray comprising thecomposition of claim
 26. 30. The tray of claim 29, wherein theelectronic part is a semiconductor, an optical data recording medium ora hard disk.
 31. The part of claim 6, wherein the polycarbonatecopolymer comprises 50 to 70 mol % of the recurring unit represented bythe general formula (I) and 50 to 30 mol % of the recurring unitrepresented by the general formula (II).
 32. The part of claim 6,wherein the polycarbonate copolymer comprises 5 to 35 mol % of recurringunit (component a) represented by the following general formula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II-1).


33. The part of claim 6, wherein the copolymer comprises 5 to 95 mol %of recurring unit (component a) represented by the following generalformula (I):

and 95 to 5 mol % of recurring unit (component b) represented by thefollowing general formula (II-1) and/or (II-2)